Adding upstream version 1:9.2p1.upstream/1%9.2p1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

3 files changed, 3476 insertions, 0 deletions

diff --git a/sshd_config b/sshd_config
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+++ b/sshd_config
@@ -0,0 +1,116 @@
+#	$OpenBSD: sshd_config,v 1.104 2021/07/02 05:11:21 dtucker Exp $
+
+# This is the sshd server system-wide configuration file.  See
+# sshd_config(5) for more information.
+
+# This sshd was compiled with PATH=/usr/bin:/bin:/usr/sbin:/sbin
+
+# The strategy used for options in the default sshd_config shipped with
+# OpenSSH is to specify options with their default value where
+# possible, but leave them commented.  Uncommented options override the
+# default value.
+
+#Port 22
+#AddressFamily any
+#ListenAddress 0.0.0.0
+#ListenAddress ::
+
+#HostKey /etc/ssh/ssh_host_rsa_key
+#HostKey /etc/ssh/ssh_host_ecdsa_key
+#HostKey /etc/ssh/ssh_host_ed25519_key
+
+# Ciphers and keying
+#RekeyLimit default none
+
+# Logging
+#SyslogFacility AUTH
+#LogLevel INFO
+
+# Authentication:
+
+#LoginGraceTime 2m
+#PermitRootLogin prohibit-password
+#StrictModes yes
+#MaxAuthTries 6
+#MaxSessions 10
+
+#PubkeyAuthentication yes
+
+# The default is to check both .ssh/authorized_keys and .ssh/authorized_keys2
+# but this is overridden so installations will only check .ssh/authorized_keys
+AuthorizedKeysFile	.ssh/authorized_keys
+
+#AuthorizedPrincipalsFile none
+
+#AuthorizedKeysCommand none
+#AuthorizedKeysCommandUser nobody
+
+# For this to work you will also need host keys in /etc/ssh/ssh_known_hosts
+#HostbasedAuthentication no
+# Change to yes if you don't trust ~/.ssh/known_hosts for
+# HostbasedAuthentication
+#IgnoreUserKnownHosts no
+# Don't read the user's ~/.rhosts and ~/.shosts files
+#IgnoreRhosts yes
+
+# To disable tunneled clear text passwords, change to no here!
+#PasswordAuthentication yes
+#PermitEmptyPasswords no
+
+# Change to no to disable s/key passwords
+#KbdInteractiveAuthentication yes
+
+# Kerberos options
+#KerberosAuthentication no
+#KerberosOrLocalPasswd yes
+#KerberosTicketCleanup yes
+#KerberosGetAFSToken no
+
+# GSSAPI options
+#GSSAPIAuthentication no
+#GSSAPICleanupCredentials yes
+
+# Set this to 'yes' to enable PAM authentication, account processing,
+# and session processing. If this is enabled, PAM authentication will
+# be allowed through the KbdInteractiveAuthentication and
+# PasswordAuthentication.  Depending on your PAM configuration,
+# PAM authentication via KbdInteractiveAuthentication may bypass
+# the setting of "PermitRootLogin prohibit-password".
+# If you just want the PAM account and session checks to run without
+# PAM authentication, then enable this but set PasswordAuthentication
+# and KbdInteractiveAuthentication to 'no'.
+#UsePAM no
+
+#AllowAgentForwarding yes
+#AllowTcpForwarding yes
+#GatewayPorts no
+#X11Forwarding no
+#X11DisplayOffset 10
+#X11UseLocalhost yes
+#PermitTTY yes
+#PrintMotd yes
+#PrintLastLog yes
+#TCPKeepAlive yes
+#PermitUserEnvironment no
+#Compression delayed
+#ClientAliveInterval 0
+#ClientAliveCountMax 3
+#UseDNS no
+#PidFile /var/run/sshd.pid
+#MaxStartups 10:30:100
+#PermitTunnel no
+#ChrootDirectory none
+#VersionAddendum none
+
+# no default banner path
+#Banner none
+
+# override default of no subsystems
+Subsystem	sftp	/usr/libexec/sftp-server
+
+# Example of overriding settings on a per-user basis
+#Match User anoncvs
+#	X11Forwarding no
+#	AllowTcpForwarding no
+#	PermitTTY no
+#	ForceCommand cvs server
diff --git a/sshd_config.0 b/sshd_config.0
new file mode 100644
index 0000000..b0bb6f9
--- /dev/null
+++ b/sshd_config.0
@@ -0,0 +1,1278 @@
+SSHD_CONFIG(5)                File Formats Manual               SSHD_CONFIG(5)
+
+NAME
+     sshd_config M-bM-^@M-^S OpenSSH daemon configuration file
+
+DESCRIPTION
+     sshd(8) reads configuration data from /etc/ssh/sshd_config (or the file
+     specified with -f on the command line).  The file contains keyword-
+     argument pairs, one per line.  For each keyword, the first obtained value
+     will be used.  Lines starting with M-bM-^@M-^X#M-bM-^@M-^Y and empty lines are interpreted as
+     comments.  Arguments may optionally be enclosed in double quotes (") in
+     order to represent arguments containing spaces.
+
+     The possible keywords and their meanings are as follows (note that
+     keywords are case-insensitive and arguments are case-sensitive):
+
+     AcceptEnv
+             Specifies what environment variables sent by the client will be
+             copied into the session's environ(7).  See SendEnv and SetEnv in
+             ssh_config(5) for how to configure the client.  The TERM
+             environment variable is always accepted whenever the client
+             requests a pseudo-terminal as it is required by the protocol.
+             Variables are specified by name, which may contain the wildcard
+             characters M-bM-^@M-^X*M-bM-^@M-^Y and M-bM-^@M-^X?M-bM-^@M-^Y.  Multiple environment variables may be
+             separated by whitespace or spread across multiple AcceptEnv
+             directives.  Be warned that some environment variables could be
+             used to bypass restricted user environments.  For this reason,
+             care should be taken in the use of this directive.  The default
+             is not to accept any environment variables.
+
+     AddressFamily
+             Specifies which address family should be used by sshd(8).  Valid
+             arguments are any (the default), inet (use IPv4 only), or inet6
+             (use IPv6 only).
+
+     AllowAgentForwarding
+             Specifies whether ssh-agent(1) forwarding is permitted.  The
+             default is yes.  Note that disabling agent forwarding does not
+             improve security unless users are also denied shell access, as
+             they can always install their own forwarders.
+
+     AllowGroups
+             This keyword can be followed by a list of group name patterns,
+             separated by spaces.  If specified, login is allowed only for
+             users whose primary group or supplementary group list matches one
+             of the patterns.  Only group names are valid; a numerical group
+             ID is not recognized.  By default, login is allowed for all
+             groups.  The allow/deny groups directives are processed in the
+             following order: DenyGroups, AllowGroups.
+
+             See PATTERNS in ssh_config(5) for more information on patterns.
+
+     AllowStreamLocalForwarding
+             Specifies whether StreamLocal (Unix-domain socket) forwarding is
+             permitted.  The available options are yes (the default) or all to
+             allow StreamLocal forwarding, no to prevent all StreamLocal
+             forwarding, local to allow local (from the perspective of ssh(1))
+             forwarding only or remote to allow remote forwarding only.  Note
+             that disabling StreamLocal forwarding does not improve security
+             unless users are also denied shell access, as they can always
+             install their own forwarders.
+
+     AllowTcpForwarding
+             Specifies whether TCP forwarding is permitted.  The available
+             options are yes (the default) or all to allow TCP forwarding, no
+             to prevent all TCP forwarding, local to allow local (from the
+             perspective of ssh(1)) forwarding only or remote to allow remote
+             forwarding only.  Note that disabling TCP forwarding does not
+             improve security unless users are also denied shell access, as
+             they can always install their own forwarders.
+
+     AllowUsers
+             This keyword can be followed by a list of user name patterns,
+             separated by spaces.  If specified, login is allowed only for
+             user names that match one of the patterns.  Only user names are
+             valid; a numerical user ID is not recognized.  By default, login
+             is allowed for all users.  If the pattern takes the form
+             USER@HOST then USER and HOST are separately checked, restricting
+             logins to particular users from particular hosts.  HOST criteria
+             may additionally contain addresses to match in CIDR
+             address/masklen format.  The allow/deny users directives are
+             processed in the following order: DenyUsers, AllowUsers.
+
+             See PATTERNS in ssh_config(5) for more information on patterns.
+
+     AuthenticationMethods
+             Specifies the authentication methods that must be successfully
+             completed for a user to be granted access.  This option must be
+             followed by one or more lists of comma-separated authentication
+             method names, or by the single string any to indicate the default
+             behaviour of accepting any single authentication method.  If the
+             default is overridden, then successful authentication requires
+             completion of every method in at least one of these lists.
+
+             For example, "publickey,password publickey,keyboard-interactive"
+             would require the user to complete public key authentication,
+             followed by either password or keyboard interactive
+             authentication.  Only methods that are next in one or more lists
+             are offered at each stage, so for this example it would not be
+             possible to attempt password or keyboard-interactive
+             authentication before public key.
+
+             For keyboard interactive authentication it is also possible to
+             restrict authentication to a specific device by appending a colon
+             followed by the device identifier bsdauth or pam.  depending on
+             the server configuration.  For example,
+             "keyboard-interactive:bsdauth" would restrict keyboard
+             interactive authentication to the bsdauth device.
+
+             If the publickey method is listed more than once, sshd(8)
+             verifies that keys that have been used successfully are not
+             reused for subsequent authentications.  For example,
+             "publickey,publickey" requires successful authentication using
+             two different public keys.
+
+             Note that each authentication method listed should also be
+             explicitly enabled in the configuration.
+
+             The available authentication methods are: "gssapi-with-mic",
+             "hostbased", "keyboard-interactive", "none" (used for access to
+             password-less accounts when PermitEmptyPasswords is enabled),
+             "password" and "publickey".
+
+     AuthorizedKeysCommand
+             Specifies a program to be used to look up the user's public keys.
+             The program must be owned by root, not writable by group or
+             others and specified by an absolute path.  Arguments to
+             AuthorizedKeysCommand accept the tokens described in the TOKENS
+             section.  If no arguments are specified then the username of the
+             target user is used.
+
+             The program should produce on standard output zero or more lines
+             of authorized_keys output (see AUTHORIZED_KEYS in sshd(8)).
+             AuthorizedKeysCommand is tried after the usual AuthorizedKeysFile
+             files and will not be executed if a matching key is found there.
+             By default, no AuthorizedKeysCommand is run.
+
+     AuthorizedKeysCommandUser
+             Specifies the user under whose account the AuthorizedKeysCommand
+             is run.  It is recommended to use a dedicated user that has no
+             other role on the host than running authorized keys commands.  If
+             AuthorizedKeysCommand is specified but AuthorizedKeysCommandUser
+             is not, then sshd(8) will refuse to start.
+
+     AuthorizedKeysFile
+             Specifies the file that contains the public keys used for user
+             authentication.  The format is described in the AUTHORIZED_KEYS
+             FILE FORMAT section of sshd(8).  Arguments to AuthorizedKeysFile
+             accept the tokens described in the TOKENS section.  After
+             expansion, AuthorizedKeysFile is taken to be an absolute path or
+             one relative to the user's home directory.  Multiple files may be
+             listed, separated by whitespace.  Alternately this option may be
+             set to none to skip checking for user keys in files.  The default
+             is ".ssh/authorized_keys .ssh/authorized_keys2".
+
+     AuthorizedPrincipalsCommand
+             Specifies a program to be used to generate the list of allowed
+             certificate principals as per AuthorizedPrincipalsFile.  The
+             program must be owned by root, not writable by group or others
+             and specified by an absolute path.  Arguments to
+             AuthorizedPrincipalsCommand accept the tokens described in the
+             TOKENS section.  If no arguments are specified then the username
+             of the target user is used.
+
+             The program should produce on standard output zero or more lines
+             of AuthorizedPrincipalsFile output.  If either
+             AuthorizedPrincipalsCommand or AuthorizedPrincipalsFile is
+             specified, then certificates offered by the client for
+             authentication must contain a principal that is listed.  By
+             default, no AuthorizedPrincipalsCommand is run.
+
+     AuthorizedPrincipalsCommandUser
+             Specifies the user under whose account the
+             AuthorizedPrincipalsCommand is run.  It is recommended to use a
+             dedicated user that has no other role on the host than running
+             authorized principals commands.  If AuthorizedPrincipalsCommand
+             is specified but AuthorizedPrincipalsCommandUser is not, then
+             sshd(8) will refuse to start.
+
+     AuthorizedPrincipalsFile
+             Specifies a file that lists principal names that are accepted for
+             certificate authentication.  When using certificates signed by a
+             key listed in TrustedUserCAKeys, this file lists names, one of
+             which must appear in the certificate for it to be accepted for
+             authentication.  Names are listed one per line preceded by key
+             options (as described in AUTHORIZED_KEYS FILE FORMAT in sshd(8)).
+             Empty lines and comments starting with M-bM-^@M-^X#M-bM-^@M-^Y are ignored.
+
+             Arguments to AuthorizedPrincipalsFile accept the tokens described
+             in the TOKENS section.  After expansion, AuthorizedPrincipalsFile
+             is taken to be an absolute path or one relative to the user's
+             home directory.  The default is none, i.e. not to use a
+             principals file M-bM-^@M-^S in this case, the username of the user must
+             appear in a certificate's principals list for it to be accepted.
+
+             Note that AuthorizedPrincipalsFile is only used when
+             authentication proceeds using a CA listed in TrustedUserCAKeys
+             and is not consulted for certification authorities trusted via
+             ~/.ssh/authorized_keys, though the principals= key option offers
+             a similar facility (see sshd(8) for details).
+
+     Banner  The contents of the specified file are sent to the remote user
+             before authentication is allowed.  If the argument is none then
+             no banner is displayed.  By default, no banner is displayed.
+
+     CASignatureAlgorithms
+             Specifies which algorithms are allowed for signing of
+             certificates by certificate authorities (CAs).  The default is:
+
+                   ssh-ed25519,ecdsa-sha2-nistp256,
+                   ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
+                   sk-ssh-ed25519@openssh.com,
+                   sk-ecdsa-sha2-nistp256@openssh.com,
+                   rsa-sha2-512,rsa-sha2-256
+
+             If the specified list begins with a M-bM-^@M-^X+M-bM-^@M-^Y character, then the
+             specified algorithms will be appended to the default set instead
+             of replacing them.  If the specified list begins with a M-bM-^@M-^X-M-bM-^@M-^Y
+             character, then the specified algorithms (including wildcards)
+             will be removed from the default set instead of replacing them.
+
+             Certificates signed using other algorithms will not be accepted
+             for public key or host-based authentication.
+
+     ChannelTimeout
+             Specifies whether and how quickly sshd(8) should close inactive
+             channels.  Timeouts are specified as one or more M-bM-^@M-^\type=intervalM-bM-^@M-^]
+             pairs separated by whitespace, where the M-bM-^@M-^\typeM-bM-^@M-^] must be a channel
+             type name (as described in the table below), optionally
+             containing wildcard characters.
+
+             The timeout value M-bM-^@M-^\intervalM-bM-^@M-^] is specified in seconds or may use
+             any of the units documented in the TIME FORMATS section.  For
+             example, M-bM-^@M-^\session:*=5mM-bM-^@M-^] would cause all sessions to terminate
+             after five minutes of inactivity.  Specifying a zero value
+             disables the inactivity timeout.
+
+             The available channel types include:
+
+             agent-connection
+                     Open connections to ssh-agent(1).
+
+             direct-tcpip, direct-streamlocal@openssh.com
+                     Open TCP or Unix socket (respectively) connections that
+                     have been established from a ssh(1) local forwarding,
+                     i.e. LocalForward or DynamicForward.
+
+             forwarded-tcpip, forwarded-streamlocal@openssh.com
+                     Open TCP or Unix socket (respectively) connections that
+                     have been established to a sshd(8) listening on behalf of
+                     a ssh(1) remote forwarding, i.e. RemoteForward.
+
+             session:command
+                     Command execution sessions.
+
+             session:shell
+                     Interactive shell sessions.
+
+             session:subsystem:...
+                     Subsystem sessions, e.g. for sftp(1), which could be
+                     identified as session:subsystem:sftp.
+
+             x11-connection
+                     Open X11 forwarding sessions.
+
+             Note that in all the above cases, terminating an inactive session
+             does not guarantee to remove all resources associated with the
+             session, e.g. shell processes or X11 clients relating to the
+             session may continue to execute.
+
+             Moreover, terminating an inactive channel or session does not
+             necessarily close the SSH connection, nor does it prevent a
+             client from requesting another channel of the same type.  In
+             particular, expiring an inactive forwarding session does not
+             prevent another identical forwarding from being subsequently
+             created.  See also UnusedConnectionTimeout, which may be used in
+             conjunction with this option.
+
+             The default is not to expire channels of any type for inactivity.
+
+     ChrootDirectory
+             Specifies the pathname of a directory to chroot(2) to after
+             authentication.  At session startup sshd(8) checks that all
+             components of the pathname are root-owned directories which are
+             not writable by any other user or group.  After the chroot,
+             sshd(8) changes the working directory to the user's home
+             directory.  Arguments to ChrootDirectory accept the tokens
+             described in the TOKENS section.
+
+             The ChrootDirectory must contain the necessary files and
+             directories to support the user's session.  For an interactive
+             session this requires at least a shell, typically sh(1), and
+             basic /dev nodes such as null(4), zero(4), stdin(4), stdout(4),
+             stderr(4), and tty(4) devices.  For file transfer sessions using
+             SFTP no additional configuration of the environment is necessary
+             if the in-process sftp-server is used, though sessions which use
+             logging may require /dev/log inside the chroot directory on some
+             operating systems (see sftp-server(8) for details).
+
+             For safety, it is very important that the directory hierarchy be
+             prevented from modification by other processes on the system
+             (especially those outside the jail).  Misconfiguration can lead
+             to unsafe environments which sshd(8) cannot detect.
+
+             The default is none, indicating not to chroot(2).
+
+     Ciphers
+             Specifies the ciphers allowed.  Multiple ciphers must be comma-
+             separated.  If the specified list begins with a M-bM-^@M-^X+M-bM-^@M-^Y character,
+             then the specified ciphers will be appended to the default set
+             instead of replacing them.  If the specified list begins with a
+             M-bM-^@M-^X-M-bM-^@M-^Y character, then the specified ciphers (including wildcards)
+             will be removed from the default set instead of replacing them.
+             If the specified list begins with a M-bM-^@M-^X^M-bM-^@M-^Y character, then the
+             specified ciphers will be placed at the head of the default set.
+
+             The supported ciphers are:
+
+                   3des-cbc
+                   aes128-cbc
+                   aes192-cbc
+                   aes256-cbc
+                   aes128-ctr
+                   aes192-ctr
+                   aes256-ctr
+                   aes128-gcm@openssh.com
+                   aes256-gcm@openssh.com
+                   chacha20-poly1305@openssh.com
+
+             The default is:
+
+                   chacha20-poly1305@openssh.com,
+                   aes128-ctr,aes192-ctr,aes256-ctr,
+                   aes128-gcm@openssh.com,aes256-gcm@openssh.com
+
+             The list of available ciphers may also be obtained using "ssh -Q
+             cipher".
+
+     ClientAliveCountMax
+             Sets the number of client alive messages which may be sent
+             without sshd(8) receiving any messages back from the client.  If
+             this threshold is reached while client alive messages are being
+             sent, sshd will disconnect the client, terminating the session.
+             It is important to note that the use of client alive messages is
+             very different from TCPKeepAlive.  The client alive messages are
+             sent through the encrypted channel and therefore will not be
+             spoofable.  The TCP keepalive option enabled by TCPKeepAlive is
+             spoofable.  The client alive mechanism is valuable when the
+             client or server depend on knowing when a connection has become
+             unresponsive.
+
+             The default value is 3.  If ClientAliveInterval is set to 15, and
+             ClientAliveCountMax is left at the default, unresponsive SSH
+             clients will be disconnected after approximately 45 seconds.
+             Setting a zero ClientAliveCountMax disables connection
+             termination.
+
+     ClientAliveInterval
+             Sets a timeout interval in seconds after which if no data has
+             been received from the client, sshd(8) will send a message
+             through the encrypted channel to request a response from the
+             client.  The default is 0, indicating that these messages will
+             not be sent to the client.
+
+     Compression
+             Specifies whether compression is enabled after the user has
+             authenticated successfully.  The argument must be yes, delayed (a
+             legacy synonym for yes) or no.  The default is yes.
+
+     DenyGroups
+             This keyword can be followed by a list of group name patterns,
+             separated by spaces.  Login is disallowed for users whose primary
+             group or supplementary group list matches one of the patterns.
+             Only group names are valid; a numerical group ID is not
+             recognized.  By default, login is allowed for all groups.  The
+             allow/deny groups directives are processed in the following
+             order: DenyGroups, AllowGroups.
+
+             See PATTERNS in ssh_config(5) for more information on patterns.
+
+     DenyUsers
+             This keyword can be followed by a list of user name patterns,
+             separated by spaces.  Login is disallowed for user names that
+             match one of the patterns.  Only user names are valid; a
+             numerical user ID is not recognized.  By default, login is
+             allowed for all users.  If the pattern takes the form USER@HOST
+             then USER and HOST are separately checked, restricting logins to
+             particular users from particular hosts.  HOST criteria may
+             additionally contain addresses to match in CIDR address/masklen
+             format.  The allow/deny users directives are processed in the
+             following order: DenyUsers, AllowUsers.
+
+             See PATTERNS in ssh_config(5) for more information on patterns.
+
+     DisableForwarding
+             Disables all forwarding features, including X11, ssh-agent(1),
+             TCP and StreamLocal.  This option overrides all other forwarding-
+             related options and may simplify restricted configurations.
+
+     ExposeAuthInfo
+             Writes a temporary file containing a list of authentication
+             methods and public credentials (e.g. keys) used to authenticate
+             the user.  The location of the file is exposed to the user
+             session through the SSH_USER_AUTH environment variable.  The
+             default is no.
+
+     FingerprintHash
+             Specifies the hash algorithm used when logging key fingerprints.
+             Valid options are: md5 and sha256.  The default is sha256.
+
+     ForceCommand
+             Forces the execution of the command specified by ForceCommand,
+             ignoring any command supplied by the client and ~/.ssh/rc if
+             present.  The command is invoked by using the user's login shell
+             with the -c option.  This applies to shell, command, or subsystem
+             execution.  It is most useful inside a Match block.  The command
+             originally supplied by the client is available in the
+             SSH_ORIGINAL_COMMAND environment variable.  Specifying a command
+             of internal-sftp will force the use of an in-process SFTP server
+             that requires no support files when used with ChrootDirectory.
+             The default is none.
+
+     GatewayPorts
+             Specifies whether remote hosts are allowed to connect to ports
+             forwarded for the client.  By default, sshd(8) binds remote port
+             forwardings to the loopback address.  This prevents other remote
+             hosts from connecting to forwarded ports.  GatewayPorts can be
+             used to specify that sshd should allow remote port forwardings to
+             bind to non-loopback addresses, thus allowing other hosts to
+             connect.  The argument may be no to force remote port forwardings
+             to be available to the local host only, yes to force remote port
+             forwardings to bind to the wildcard address, or clientspecified
+             to allow the client to select the address to which the forwarding
+             is bound.  The default is no.
+
+     GSSAPIAuthentication
+             Specifies whether user authentication based on GSSAPI is allowed.
+             The default is no.
+
+     GSSAPICleanupCredentials
+             Specifies whether to automatically destroy the user's credentials
+             cache on logout.  The default is yes.
+
+     GSSAPIStrictAcceptorCheck
+             Determines whether to be strict about the identity of the GSSAPI
+             acceptor a client authenticates against.  If set to yes then the
+             client must authenticate against the host service on the current
+             hostname.  If set to no then the client may authenticate against
+             any service key stored in the machine's default store.  This
+             facility is provided to assist with operation on multi homed
+             machines.  The default is yes.
+
+     HostbasedAcceptedAlgorithms
+             Specifies the signature algorithms that will be accepted for
+             hostbased authentication as a list of comma-separated patterns.
+             Alternately if the specified list begins with a M-bM-^@M-^X+M-bM-^@M-^Y character,
+             then the specified signature algorithms will be appended to the
+             default set instead of replacing them.  If the specified list
+             begins with a M-bM-^@M-^X-M-bM-^@M-^Y character, then the specified signature
+             algorithms (including wildcards) will be removed from the default
+             set instead of replacing them.  If the specified list begins with
+             a M-bM-^@M-^X^M-bM-^@M-^Y character, then the specified signature algorithms will be
+             placed at the head of the default set.  The default for this
+             option is:
+
+                ssh-ed25519-cert-v01@openssh.com,
+                ecdsa-sha2-nistp256-cert-v01@openssh.com,
+                ecdsa-sha2-nistp384-cert-v01@openssh.com,
+                ecdsa-sha2-nistp521-cert-v01@openssh.com,
+                sk-ssh-ed25519-cert-v01@openssh.com,
+                sk-ecdsa-sha2-nistp256-cert-v01@openssh.com,
+                rsa-sha2-512-cert-v01@openssh.com,
+                rsa-sha2-256-cert-v01@openssh.com,
+                ssh-ed25519,
+                ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
+                sk-ssh-ed25519@openssh.com,
+                sk-ecdsa-sha2-nistp256@openssh.com,
+                rsa-sha2-512,rsa-sha2-256
+
+             The list of available signature algorithms may also be obtained
+             using "ssh -Q HostbasedAcceptedAlgorithms".  This was formerly
+             named HostbasedAcceptedKeyTypes.
+
+     HostbasedAuthentication
+             Specifies whether rhosts or /etc/hosts.equiv authentication
+             together with successful public key client host authentication is
+             allowed (host-based authentication).  The default is no.
+
+     HostbasedUsesNameFromPacketOnly
+             Specifies whether or not the server will attempt to perform a
+             reverse name lookup when matching the name in the ~/.shosts,
+             ~/.rhosts, and /etc/hosts.equiv files during
+             HostbasedAuthentication.  A setting of yes means that sshd(8)
+             uses the name supplied by the client rather than attempting to
+             resolve the name from the TCP connection itself.  The default is
+             no.
+
+     HostCertificate
+             Specifies a file containing a public host certificate.  The
+             certificate's public key must match a private host key already
+             specified by HostKey.  The default behaviour of sshd(8) is not to
+             load any certificates.
+
+     HostKey
+             Specifies a file containing a private host key used by SSH.  The
+             defaults are /etc/ssh/ssh_host_ecdsa_key,
+             /etc/ssh/ssh_host_ed25519_key and /etc/ssh/ssh_host_rsa_key.
+
+             Note that sshd(8) will refuse to use a file if it is group/world-
+             accessible and that the HostKeyAlgorithms option restricts which
+             of the keys are actually used by sshd(8).
+
+             It is possible to have multiple host key files.  It is also
+             possible to specify public host key files instead.  In this case
+             operations on the private key will be delegated to an
+             ssh-agent(1).
+
+     HostKeyAgent
+             Identifies the UNIX-domain socket used to communicate with an
+             agent that has access to the private host keys.  If the string
+             "SSH_AUTH_SOCK" is specified, the location of the socket will be
+             read from the SSH_AUTH_SOCK environment variable.
+
+     HostKeyAlgorithms
+             Specifies the host key signature algorithms that the server
+             offers.  The default for this option is:
+
+                ssh-ed25519-cert-v01@openssh.com,
+                ecdsa-sha2-nistp256-cert-v01@openssh.com,
+                ecdsa-sha2-nistp384-cert-v01@openssh.com,
+                ecdsa-sha2-nistp521-cert-v01@openssh.com,
+                sk-ssh-ed25519-cert-v01@openssh.com,
+                sk-ecdsa-sha2-nistp256-cert-v01@openssh.com,
+                rsa-sha2-512-cert-v01@openssh.com,
+                rsa-sha2-256-cert-v01@openssh.com,
+                ssh-ed25519,
+                ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
+                sk-ssh-ed25519@openssh.com,
+                sk-ecdsa-sha2-nistp256@openssh.com,
+                rsa-sha2-512,rsa-sha2-256
+
+             The list of available signature algorithms may also be obtained
+             using "ssh -Q HostKeyAlgorithms".
+
+     IgnoreRhosts
+             Specifies whether to ignore per-user .rhosts and .shosts files
+             during HostbasedAuthentication.  The system-wide /etc/hosts.equiv
+             and /etc/shosts.equiv are still used regardless of this setting.
+
+             Accepted values are yes (the default) to ignore all per-user
+             files, shosts-only to allow the use of .shosts but to ignore
+             .rhosts or no to allow both .shosts and rhosts.
+
+     IgnoreUserKnownHosts
+             Specifies whether sshd(8) should ignore the user's
+             ~/.ssh/known_hosts during HostbasedAuthentication and use only
+             the system-wide known hosts file /etc/ssh/ssh_known_hosts.  The
+             default is M-bM-^@M-^\noM-bM-^@M-^].
+
+     Include
+             Include the specified configuration file(s).  Multiple pathnames
+             may be specified and each pathname may contain glob(7) wildcards
+             that will be expanded and processed in lexical order.  Files
+             without absolute paths are assumed to be in /etc/ssh.  An Include
+             directive may appear inside a Match block to perform conditional
+             inclusion.
+
+     IPQoS   Specifies the IPv4 type-of-service or DSCP class for the
+             connection.  Accepted values are af11, af12, af13, af21, af22,
+             af23, af31, af32, af33, af41, af42, af43, cs0, cs1, cs2, cs3,
+             cs4, cs5, cs6, cs7, ef, le, lowdelay, throughput, reliability, a
+             numeric value, or none to use the operating system default.  This
+             option may take one or two arguments, separated by whitespace.
+             If one argument is specified, it is used as the packet class
+             unconditionally.  If two values are specified, the first is
+             automatically selected for interactive sessions and the second
+             for non-interactive sessions.  The default is af21 (Low-Latency
+             Data) for interactive sessions and cs1 (Lower Effort) for non-
+             interactive sessions.
+
+     KbdInteractiveAuthentication
+             Specifies whether to allow keyboard-interactive authentication.
+             All authentication styles from login.conf(5) are supported.  The
+             default is yes.  The argument to this keyword must be yes or no.
+             ChallengeResponseAuthentication is a deprecated alias for this.
+
+     KerberosAuthentication
+             Specifies whether the password provided by the user for
+             PasswordAuthentication will be validated through the Kerberos
+             KDC.  To use this option, the server needs a Kerberos servtab
+             which allows the verification of the KDC's identity.  The default
+             is no.
+
+     KerberosGetAFSToken
+             If AFS is active and the user has a Kerberos 5 TGT, attempt to
+             acquire an AFS token before accessing the user's home directory.
+             The default is no.
+
+     KerberosOrLocalPasswd
+             If password authentication through Kerberos fails then the
+             password will be validated via any additional local mechanism
+             such as /etc/passwd.  The default is yes.
+
+     KerberosTicketCleanup
+             Specifies whether to automatically destroy the user's ticket
+             cache file on logout.  The default is yes.
+
+     KexAlgorithms
+             Specifies the available KEX (Key Exchange) algorithms.  Multiple
+             algorithms must be comma-separated.  Alternately if the specified
+             list begins with a M-bM-^@M-^X+M-bM-^@M-^Y character, then the specified algorithms
+             will be appended to the default set instead of replacing them.
+             If the specified list begins with a M-bM-^@M-^X-M-bM-^@M-^Y character, then the
+             specified algorithms (including wildcards) will be removed from
+             the default set instead of replacing them.  If the specified list
+             begins with a M-bM-^@M-^X^M-bM-^@M-^Y character, then the specified algorithms will
+             be placed at the head of the default set.  The supported
+             algorithms are:
+
+                   curve25519-sha256
+                   curve25519-sha256@libssh.org
+                   diffie-hellman-group1-sha1
+                   diffie-hellman-group14-sha1
+                   diffie-hellman-group14-sha256
+                   diffie-hellman-group16-sha512
+                   diffie-hellman-group18-sha512
+                   diffie-hellman-group-exchange-sha1
+                   diffie-hellman-group-exchange-sha256
+                   ecdh-sha2-nistp256
+                   ecdh-sha2-nistp384
+                   ecdh-sha2-nistp521
+                   sntrup761x25519-sha512@openssh.com
+
+             The default is:
+
+                   sntrup761x25519-sha512@openssh.com,
+                   curve25519-sha256,curve25519-sha256@libssh.org,
+                   ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,
+                   diffie-hellman-group-exchange-sha256,
+                   diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,
+                   diffie-hellman-group14-sha256
+
+             The list of available key exchange algorithms may also be
+             obtained using "ssh -Q KexAlgorithms".
+
+     ListenAddress
+             Specifies the local addresses sshd(8) should listen on.  The
+             following forms may be used:
+
+                   ListenAddress hostname|address [rdomain domain]
+                   ListenAddress hostname:port [rdomain domain]
+                   ListenAddress IPv4_address:port [rdomain domain]
+                   ListenAddress [hostname|address]:port [rdomain domain]
+
+             The optional rdomain qualifier requests sshd(8) listen in an
+             explicit routing domain.  If port is not specified, sshd will
+             listen on the address and all Port options specified.  The
+             default is to listen on all local addresses on the current
+             default routing domain.  Multiple ListenAddress options are
+             permitted.  For more information on routing domains, see
+             rdomain(4).
+
+     LoginGraceTime
+             The server disconnects after this time if the user has not
+             successfully logged in.  If the value is 0, there is no time
+             limit.  The default is 120 seconds.
+
+     LogLevel
+             Gives the verbosity level that is used when logging messages from
+             sshd(8).  The possible values are: QUIET, FATAL, ERROR, INFO,
+             VERBOSE, DEBUG, DEBUG1, DEBUG2, and DEBUG3.  The default is INFO.
+             DEBUG and DEBUG1 are equivalent.  DEBUG2 and DEBUG3 each specify
+             higher levels of debugging output.  Logging with a DEBUG level
+             violates the privacy of users and is not recommended.
+
+     LogVerbose
+             Specify one or more overrides to LogLevel.  An override consists
+             of a pattern lists that matches the source file, function and
+             line number to force detailed logging for.  For example, an
+             override pattern of:
+
+                   kex.c:*:1000,*:kex_exchange_identification():*,packet.c:*
+
+             would enable detailed logging for line 1000 of kex.c, everything
+             in the kex_exchange_identification() function, and all code in
+             the packet.c file.  This option is intended for debugging and no
+             overrides are enabled by default.
+
+     MACs    Specifies the available MAC (message authentication code)
+             algorithms.  The MAC algorithm is used for data integrity
+             protection.  Multiple algorithms must be comma-separated.  If the
+             specified list begins with a M-bM-^@M-^X+M-bM-^@M-^Y character, then the specified
+             algorithms will be appended to the default set instead of
+             replacing them.  If the specified list begins with a M-bM-^@M-^X-M-bM-^@M-^Y
+             character, then the specified algorithms (including wildcards)
+             will be removed from the default set instead of replacing them.
+             If the specified list begins with a M-bM-^@M-^X^M-bM-^@M-^Y character, then the
+             specified algorithms will be placed at the head of the default
+             set.
+
+             The algorithms that contain "-etm" calculate the MAC after
+             encryption (encrypt-then-mac).  These are considered safer and
+             their use recommended.  The supported MACs are:
+
+                   hmac-md5
+                   hmac-md5-96
+                   hmac-sha1
+                   hmac-sha1-96
+                   hmac-sha2-256
+                   hmac-sha2-512
+                   umac-64@openssh.com
+                   umac-128@openssh.com
+                   hmac-md5-etm@openssh.com
+                   hmac-md5-96-etm@openssh.com
+                   hmac-sha1-etm@openssh.com
+                   hmac-sha1-96-etm@openssh.com
+                   hmac-sha2-256-etm@openssh.com
+                   hmac-sha2-512-etm@openssh.com
+                   umac-64-etm@openssh.com
+                   umac-128-etm@openssh.com
+
+             The default is:
+
+                   umac-64-etm@openssh.com,umac-128-etm@openssh.com,
+                   hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,
+                   hmac-sha1-etm@openssh.com,
+                   umac-64@openssh.com,umac-128@openssh.com,
+                   hmac-sha2-256,hmac-sha2-512,hmac-sha1
+
+             The list of available MAC algorithms may also be obtained using
+             "ssh -Q mac".
+
+     Match   Introduces a conditional block.  If all of the criteria on the
+             Match line are satisfied, the keywords on the following lines
+             override those set in the global section of the config file,
+             until either another Match line or the end of the file.  If a
+             keyword appears in multiple Match blocks that are satisfied, only
+             the first instance of the keyword is applied.
+
+             The arguments to Match are one or more criteria-pattern pairs or
+             the single token All which matches all criteria.  The available
+             criteria are User, Group, Host, LocalAddress, LocalPort, RDomain,
+             and Address (with RDomain representing the rdomain(4) on which
+             the connection was received).
+
+             The match patterns may consist of single entries or comma-
+             separated lists and may use the wildcard and negation operators
+             described in the PATTERNS section of ssh_config(5).
+
+             The patterns in an Address criteria may additionally contain
+             addresses to match in CIDR address/masklen format, such as
+             192.0.2.0/24 or 2001:db8::/32.  Note that the mask length
+             provided must be consistent with the address - it is an error to
+             specify a mask length that is too long for the address or one
+             with bits set in this host portion of the address.  For example,
+             192.0.2.0/33 and 192.0.2.0/8, respectively.
+
+             Only a subset of keywords may be used on the lines following a
+             Match keyword.  Available keywords are AcceptEnv,
+             AllowAgentForwarding, AllowGroups, AllowStreamLocalForwarding,
+             AllowTcpForwarding, AllowUsers, AuthenticationMethods,
+             AuthorizedKeysCommand, AuthorizedKeysCommandUser,
+             AuthorizedKeysFile, AuthorizedPrincipalsCommand,
+             AuthorizedPrincipalsCommandUser, AuthorizedPrincipalsFile,
+             Banner, CASignatureAlgorithms, ChannelTimeout, ChrootDirectory,
+             ClientAliveCountMax, ClientAliveInterval, DenyGroups, DenyUsers,
+             DisableForwarding, ExposeAuthInfo, ForceCommand, GatewayPorts,
+             GSSAPIAuthentication, HostbasedAcceptedAlgorithms,
+             HostbasedAuthentication, HostbasedUsesNameFromPacketOnly,
+             IgnoreRhosts, Include, IPQoS, KbdInteractiveAuthentication,
+             KerberosAuthentication, LogLevel, MaxAuthTries, MaxSessions,
+             PasswordAuthentication, PermitEmptyPasswords, PermitListen,
+             PermitOpen, PermitRootLogin, PermitTTY, PermitTunnel,
+             PermitUserRC, PubkeyAcceptedAlgorithms, PubkeyAuthentication,
+             PubkeyAuthOptions, RekeyLimit, RevokedKeys, RDomain, SetEnv,
+             StreamLocalBindMask, StreamLocalBindUnlink, TrustedUserCAKeys,
+             UnusedConnectionTimeout, X11DisplayOffset, X11Forwarding and
+             X11UseLocalhost.
+
+     MaxAuthTries
+             Specifies the maximum number of authentication attempts permitted
+             per connection.  Once the number of failures reaches half this
+             value, additional failures are logged.  The default is 6.
+
+     MaxSessions
+             Specifies the maximum number of open shell, login or subsystem
+             (e.g. sftp) sessions permitted per network connection.  Multiple
+             sessions may be established by clients that support connection
+             multiplexing.  Setting MaxSessions to 1 will effectively disable
+             session multiplexing, whereas setting it to 0 will prevent all
+             shell, login and subsystem sessions while still permitting
+             forwarding.  The default is 10.
+
+     MaxStartups
+             Specifies the maximum number of concurrent unauthenticated
+             connections to the SSH daemon.  Additional connections will be
+             dropped until authentication succeeds or the LoginGraceTime
+             expires for a connection.  The default is 10:30:100.
+
+             Alternatively, random early drop can be enabled by specifying the
+             three colon separated values start:rate:full (e.g. "10:30:60").
+             sshd(8) will refuse connection attempts with a probability of
+             rate/100 (30%) if there are currently start (10) unauthenticated
+             connections.  The probability increases linearly and all
+             connection attempts are refused if the number of unauthenticated
+             connections reaches full (60).
+
+     ModuliFile
+             Specifies the moduli(5) file that contains the Diffie-Hellman
+             groups used for the M-bM-^@M-^\diffie-hellman-group-exchange-sha1M-bM-^@M-^] and
+             M-bM-^@M-^\diffie-hellman-group-exchange-sha256M-bM-^@M-^] key exchange methods.  The
+             default is /etc/moduli.
+
+     PasswordAuthentication
+             Specifies whether password authentication is allowed.  The
+             default is yes.
+
+     PermitEmptyPasswords
+             When password authentication is allowed, it specifies whether the
+             server allows login to accounts with empty password strings.  The
+             default is no.
+
+     PermitListen
+             Specifies the addresses/ports on which a remote TCP port
+             forwarding may listen.  The listen specification must be one of
+             the following forms:
+
+                   PermitListen port
+                   PermitListen host:port
+
+             Multiple permissions may be specified by separating them with
+             whitespace.  An argument of any can be used to remove all
+             restrictions and permit any listen requests.  An argument of none
+             can be used to prohibit all listen requests.  The host name may
+             contain wildcards as described in the PATTERNS section in
+             ssh_config(5).  The wildcard M-bM-^@M-^X*M-bM-^@M-^Y can also be used in place of a
+             port number to allow all ports.  By default all port forwarding
+             listen requests are permitted.  Note that the GatewayPorts option
+             may further restrict which addresses may be listened on.  Note
+             also that ssh(1) will request a listen host of M-bM-^@M-^\localhostM-bM-^@M-^] if no
+             listen host was specifically requested, and this name is treated
+             differently to explicit localhost addresses of M-bM-^@M-^\127.0.0.1M-bM-^@M-^] and
+             M-bM-^@M-^\::1M-bM-^@M-^].
+
+     PermitOpen
+             Specifies the destinations to which TCP port forwarding is
+             permitted.  The forwarding specification must be one of the
+             following forms:
+
+                   PermitOpen host:port
+                   PermitOpen IPv4_addr:port
+                   PermitOpen [IPv6_addr]:port
+
+             Multiple forwards may be specified by separating them with
+             whitespace.  An argument of any can be used to remove all
+             restrictions and permit any forwarding requests.  An argument of
+             none can be used to prohibit all forwarding requests.  The
+             wildcard M-bM-^@M-^X*M-bM-^@M-^Y can be used for host or port to allow all hosts or
+             ports respectively.  Otherwise, no pattern matching or address
+             lookups are performed on supplied names.  By default all port
+             forwarding requests are permitted.
+
+     PermitRootLogin
+             Specifies whether root can log in using ssh(1).  The argument
+             must be yes, prohibit-password, forced-commands-only, or no.  The
+             default is prohibit-password.
+
+             If this option is set to prohibit-password (or its deprecated
+             alias, without-password), password and keyboard-interactive
+             authentication are disabled for root.
+
+             If this option is set to forced-commands-only, root login with
+             public key authentication will be allowed, but only if the
+             command option has been specified (which may be useful for taking
+             remote backups even if root login is normally not allowed).  All
+             other authentication methods are disabled for root.
+
+             If this option is set to no, root is not allowed to log in.
+
+     PermitTTY
+             Specifies whether pty(4) allocation is permitted.  The default is
+             yes.
+
+     PermitTunnel
+             Specifies whether tun(4) device forwarding is allowed.  The
+             argument must be yes, point-to-point (layer 3), ethernet (layer
+             2), or no.  Specifying yes permits both point-to-point and
+             ethernet.  The default is no.
+
+             Independent of this setting, the permissions of the selected
+             tun(4) device must allow access to the user.
+
+     PermitUserEnvironment
+             Specifies whether ~/.ssh/environment and environment= options in
+             ~/.ssh/authorized_keys are processed by sshd(8).  Valid options
+             are yes, no or a pattern-list specifying which environment
+             variable names to accept (for example "LANG,LC_*").  The default
+             is no.  Enabling environment processing may enable users to
+             bypass access restrictions in some configurations using
+             mechanisms such as LD_PRELOAD.
+
+     PermitUserRC
+             Specifies whether any ~/.ssh/rc file is executed.  The default is
+             yes.
+
+     PerSourceMaxStartups
+             Specifies the number of unauthenticated connections allowed from
+             a given source address, or M-bM-^@M-^\noneM-bM-^@M-^] if there is no limit.  This
+             limit is applied in addition to MaxStartups, whichever is lower.
+             The default is none.
+
+     PerSourceNetBlockSize
+             Specifies the number of bits of source address that are grouped
+             together for the purposes of applying PerSourceMaxStartups
+             limits.  Values for IPv4 and optionally IPv6 may be specified,
+             separated by a colon.  The default is 32:128, which means each
+             address is considered individually.
+
+     PidFile
+             Specifies the file that contains the process ID of the SSH
+             daemon, or none to not write one.  The default is
+             /var/run/sshd.pid.
+
+     Port    Specifies the port number that sshd(8) listens on.  The default
+             is 22.  Multiple options of this type are permitted.  See also
+             ListenAddress.
+
+     PrintLastLog
+             Specifies whether sshd(8) should print the date and time of the
+             last user login when a user logs in interactively.  The default
+             is yes.
+
+     PrintMotd
+             Specifies whether sshd(8) should print /etc/motd when a user logs
+             in interactively.  (On some systems it is also printed by the
+             shell, /etc/profile, or equivalent.)  The default is yes.
+
+     PubkeyAcceptedAlgorithms
+             Specifies the signature algorithms that will be accepted for
+             public key authentication as a list of comma-separated patterns.
+             Alternately if the specified list begins with a M-bM-^@M-^X+M-bM-^@M-^Y character,
+             then the specified algorithms will be appended to the default set
+             instead of replacing them.  If the specified list begins with a
+             M-bM-^@M-^X-M-bM-^@M-^Y character, then the specified algorithms (including
+             wildcards) will be removed from the default set instead of
+             replacing them.  If the specified list begins with a M-bM-^@M-^X^M-bM-^@M-^Y
+             character, then the specified algorithms will be placed at the
+             head of the default set.  The default for this option is:
+
+                ssh-ed25519-cert-v01@openssh.com,
+                ecdsa-sha2-nistp256-cert-v01@openssh.com,
+                ecdsa-sha2-nistp384-cert-v01@openssh.com,
+                ecdsa-sha2-nistp521-cert-v01@openssh.com,
+                sk-ssh-ed25519-cert-v01@openssh.com,
+                sk-ecdsa-sha2-nistp256-cert-v01@openssh.com,
+                rsa-sha2-512-cert-v01@openssh.com,
+                rsa-sha2-256-cert-v01@openssh.com,
+                ssh-ed25519,
+                ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
+                sk-ssh-ed25519@openssh.com,
+                sk-ecdsa-sha2-nistp256@openssh.com,
+                rsa-sha2-512,rsa-sha2-256
+
+             The list of available signature algorithms may also be obtained
+             using "ssh -Q PubkeyAcceptedAlgorithms".
+
+     PubkeyAuthOptions
+             Sets one or more public key authentication options.  The
+             supported keywords are: none (the default; indicating no
+             additional options are enabled), touch-required and
+             verify-required.
+
+             The touch-required option causes public key authentication using
+             a FIDO authenticator algorithm (i.e. ecdsa-sk or ed25519-sk) to
+             always require the signature to attest that a physically present
+             user explicitly confirmed the authentication (usually by touching
+             the authenticator).  By default, sshd(8) requires user presence
+             unless overridden with an authorized_keys option.  The
+             touch-required flag disables this override.
+
+             The verify-required option requires a FIDO key signature attest
+             that the user was verified, e.g. via a PIN.
+
+             Neither the touch-required or verify-required options have any
+             effect for other, non-FIDO, public key types.
+
+     PubkeyAuthentication
+             Specifies whether public key authentication is allowed.  The
+             default is yes.
+
+     RekeyLimit
+             Specifies the maximum amount of data that may be transmitted or
+             received before the session key is renegotiated, optionally
+             followed by a maximum amount of time that may pass before the
+             session key is renegotiated.  The first argument is specified in
+             bytes and may have a suffix of M-bM-^@M-^XKM-bM-^@M-^Y, M-bM-^@M-^XMM-bM-^@M-^Y, or M-bM-^@M-^XGM-bM-^@M-^Y to indicate
+             Kilobytes, Megabytes, or Gigabytes, respectively.  The default is
+             between M-bM-^@M-^X1GM-bM-^@M-^Y and M-bM-^@M-^X4GM-bM-^@M-^Y, depending on the cipher.  The optional
+             second value is specified in seconds and may use any of the units
+             documented in the TIME FORMATS section.  The default value for
+             RekeyLimit is default none, which means that rekeying is
+             performed after the cipher's default amount of data has been sent
+             or received and no time based rekeying is done.
+
+     RequiredRSASize
+             Specifies the minimum RSA key size (in bits) that sshd(8) will
+             accept.  User and host-based authentication keys smaller than
+             this limit will be refused.  The default is 1024 bits.  Note that
+             this limit may only be raised from the default.
+
+     RevokedKeys
+             Specifies revoked public keys file, or none to not use one.  Keys
+             listed in this file will be refused for public key
+             authentication.  Note that if this file is not readable, then
+             public key authentication will be refused for all users.  Keys
+             may be specified as a text file, listing one public key per line,
+             or as an OpenSSH Key Revocation List (KRL) as generated by
+             ssh-keygen(1).  For more information on KRLs, see the KEY
+             REVOCATION LISTS section in ssh-keygen(1).
+
+     RDomain
+             Specifies an explicit routing domain that is applied after
+             authentication has completed.  The user session, as well as any
+             forwarded or listening IP sockets, will be bound to this
+             rdomain(4).  If the routing domain is set to %D, then the domain
+             in which the incoming connection was received will be applied.
+
+     SecurityKeyProvider
+             Specifies a path to a library that will be used when loading FIDO
+             authenticator-hosted keys, overriding the default of using the
+             built-in USB HID support.
+
+     SetEnv  Specifies one or more environment variables to set in child
+             sessions started by sshd(8) as M-bM-^@M-^\NAME=VALUEM-bM-^@M-^].  The environment
+             value may be quoted (e.g. if it contains whitespace characters).
+             Environment variables set by SetEnv override the default
+             environment and any variables specified by the user via AcceptEnv
+             or PermitUserEnvironment.
+
+     StreamLocalBindMask
+             Sets the octal file creation mode mask (umask) used when creating
+             a Unix-domain socket file for local or remote port forwarding.
+             This option is only used for port forwarding to a Unix-domain
+             socket file.
+
+             The default value is 0177, which creates a Unix-domain socket
+             file that is readable and writable only by the owner.  Note that
+             not all operating systems honor the file mode on Unix-domain
+             socket files.
+
+     StreamLocalBindUnlink
+             Specifies whether to remove an existing Unix-domain socket file
+             for local or remote port forwarding before creating a new one.
+             If the socket file already exists and StreamLocalBindUnlink is
+             not enabled, sshd will be unable to forward the port to the Unix-
+             domain socket file.  This option is only used for port forwarding
+             to a Unix-domain socket file.
+
+             The argument must be yes or no.  The default is no.
+
+     StrictModes
+             Specifies whether sshd(8) should check file modes and ownership
+             of the user's files and home directory before accepting login.
+             This is normally desirable because novices sometimes accidentally
+             leave their directory or files world-writable.  The default is
+             yes.  Note that this does not apply to ChrootDirectory, whose
+             permissions and ownership are checked unconditionally.
+
+     Subsystem
+             Configures an external subsystem (e.g. file transfer daemon).
+             Arguments should be a subsystem name and a command (with optional
+             arguments) to execute upon subsystem request.
+
+             The command sftp-server implements the SFTP file transfer
+             subsystem.
+
+             Alternately the name internal-sftp implements an in-process SFTP
+             server.  This may simplify configurations using ChrootDirectory
+             to force a different filesystem root on clients.
+
+             By default no subsystems are defined.
+
+     SyslogFacility
+             Gives the facility code that is used when logging messages from
+             sshd(8).  The possible values are: DAEMON, USER, AUTH, LOCAL0,
+             LOCAL1, LOCAL2, LOCAL3, LOCAL4, LOCAL5, LOCAL6, LOCAL7.  The
+             default is AUTH.
+
+     TCPKeepAlive
+             Specifies whether the system should send TCP keepalive messages
+             to the other side.  If they are sent, death of the connection or
+             crash of one of the machines will be properly noticed.  However,
+             this means that connections will die if the route is down
+             temporarily, and some people find it annoying.  On the other
+             hand, if TCP keepalives are not sent, sessions may hang
+             indefinitely on the server, leaving "ghost" users and consuming
+             server resources.
+
+             The default is yes (to send TCP keepalive messages), and the
+             server will notice if the network goes down or the client host
+             crashes.  This avoids infinitely hanging sessions.
+
+             To disable TCP keepalive messages, the value should be set to no.
+
+     TrustedUserCAKeys
+             Specifies a file containing public keys of certificate
+             authorities that are trusted to sign user certificates for
+             authentication, or none to not use one.  Keys are listed one per
+             line; empty lines and comments starting with M-bM-^@M-^X#M-bM-^@M-^Y are allowed.  If
+             a certificate is presented for authentication and has its signing
+             CA key listed in this file, then it may be used for
+             authentication for any user listed in the certificate's
+             principals list.  Note that certificates that lack a list of
+             principals will not be permitted for authentication using
+             TrustedUserCAKeys.  For more details on certificates, see the
+             CERTIFICATES section in ssh-keygen(1).
+
+     UnusedConnectionTimeout
+             Specifies whether and how quickly sshd(8) should close client
+             connections with no open channels.  Open channels include active
+             shell, command execution or subsystem sessions, connected
+             network, socket, agent or X11 forwardings.  Forwarding listeners,
+             such as those from the ssh(1) -R flag, are not considered as open
+             channels and do not prevent the timeout.  The timeout value is
+             specified in seconds or may use any of the units documented in
+             the TIME FORMATS section.
+
+             Note that this timeout starts when the client connection
+             completes user authentication but before the client has an
+             opportunity to open any channels.  Caution should be used when
+             using short timeout values, as they may not provide sufficient
+             time for the client to request and open its channels before
+             terminating the connection.
+
+             The default none is to never expire connections for having no
+             open channels.  This option may be useful in conjunction with
+             ChannelTimeout.
+
+     UseDNS  Specifies whether sshd(8) should look up the remote host name,
+             and to check that the resolved host name for the remote IP
+             address maps back to the very same IP address.
+
+             If this option is set to no (the default) then only addresses and
+             not host names may be used in ~/.ssh/authorized_keys from and
+             sshd_config Match Host directives.
+
+     UsePAM  Enables the Pluggable Authentication Module interface.  If set to
+             yes this will enable PAM authentication using
+             KbdInteractiveAuthentication and PasswordAuthentication in
+             addition to PAM account and session module processing for all
+             authentication types.
+
+             Because PAM keyboard-interactive authentication usually serves an
+             equivalent role to password authentication, you should disable
+             either PasswordAuthentication or KbdInteractiveAuthentication.
+
+             If UsePAM is enabled, you will not be able to run sshd(8) as a
+             non-root user.  The default is no.
+
+     VersionAddendum
+             Optionally specifies additional text to append to the SSH
+             protocol banner sent by the server upon connection.  The default
+             is none.
+
+     X11DisplayOffset
+             Specifies the first display number available for sshd(8)'s X11
+             forwarding.  This prevents sshd from interfering with real X11
+             servers.  The default is 10.
+
+     X11Forwarding
+             Specifies whether X11 forwarding is permitted.  The argument must
+             be yes or no.  The default is no.
+
+             When X11 forwarding is enabled, there may be additional exposure
+             to the server and to client displays if the sshd(8) proxy display
+             is configured to listen on the wildcard address (see
+             X11UseLocalhost), though this is not the default.  Additionally,
+             the authentication spoofing and authentication data verification
+             and substitution occur on the client side.  The security risk of
+             using X11 forwarding is that the client's X11 display server may
+             be exposed to attack when the SSH client requests forwarding (see
+             the warnings for ForwardX11 in ssh_config(5)).  A system
+             administrator may have a stance in which they want to protect
+             clients that may expose themselves to attack by unwittingly
+             requesting X11 forwarding, which can warrant a no setting.
+
+             Note that disabling X11 forwarding does not prevent users from
+             forwarding X11 traffic, as users can always install their own
+             forwarders.
+
+     X11UseLocalhost
+             Specifies whether sshd(8) should bind the X11 forwarding server
+             to the loopback address or to the wildcard address.  By default,
+             sshd binds the forwarding server to the loopback address and sets
+             the hostname part of the DISPLAY environment variable to
+             localhost.  This prevents remote hosts from connecting to the
+             proxy display.  However, some older X11 clients may not function
+             with this configuration.  X11UseLocalhost may be set to no to
+             specify that the forwarding server should be bound to the
+             wildcard address.  The argument must be yes or no.  The default
+             is yes.
+
+     XAuthLocation
+             Specifies the full pathname of the xauth(1) program, or none to
+             not use one.  The default is /usr/X11R6/bin/xauth.
+
+TIME FORMATS
+     sshd(8) command-line arguments and configuration file options that
+     specify time may be expressed using a sequence of the form:
+     time[qualifier], where time is a positive integer value and qualifier is
+     one of the following:
+
+           M-bM-^_M-(noneM-bM-^_M-)  seconds
+           s | S   seconds
+           m | M   minutes
+           h | H   hours
+           d | D   days
+           w | W   weeks
+
+     Each member of the sequence is added together to calculate the total time
+     value.
+
+     Time format examples:
+
+           600     600 seconds (10 minutes)
+           10m     10 minutes
+           1h30m   1 hour 30 minutes (90 minutes)
+
+TOKENS
+     Arguments to some keywords can make use of tokens, which are expanded at
+     runtime:
+
+           %%    A literal M-bM-^@M-^X%M-bM-^@M-^Y.
+           %D    The routing domain in which the incoming connection was
+                 received.
+           %F    The fingerprint of the CA key.
+           %f    The fingerprint of the key or certificate.
+           %h    The home directory of the user.
+           %i    The key ID in the certificate.
+           %K    The base64-encoded CA key.
+           %k    The base64-encoded key or certificate for authentication.
+           %s    The serial number of the certificate.
+           %T    The type of the CA key.
+           %t    The key or certificate type.
+           %U    The numeric user ID of the target user.
+           %u    The username.
+
+     AuthorizedKeysCommand accepts the tokens %%, %f, %h, %k, %t, %U, and %u.
+
+     AuthorizedKeysFile accepts the tokens %%, %h, %U, and %u.
+
+     AuthorizedPrincipalsCommand accepts the tokens %%, %F, %f, %h, %i, %K,
+     %k, %s, %T, %t, %U, and %u.
+
+     AuthorizedPrincipalsFile accepts the tokens %%, %h, %U, and %u.
+
+     ChrootDirectory accepts the tokens %%, %h, %U, and %u.
+
+     RoutingDomain accepts the token %D.
+
+FILES
+     /etc/ssh/sshd_config
+             Contains configuration data for sshd(8).  This file should be
+             writable by root only, but it is recommended (though not
+             necessary) that it be world-readable.
+
+SEE ALSO
+     sftp-server(8), sshd(8)
+
+AUTHORS
+     OpenSSH is a derivative of the original and free ssh 1.2.12 release by
+     Tatu Ylonen.  Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos, Theo
+     de Raadt and Dug Song removed many bugs, re-added newer features and
+     created OpenSSH.  Markus Friedl contributed the support for SSH protocol
+     versions 1.5 and 2.0.  Niels Provos and Markus Friedl contributed support
+     for privilege separation.
+
+OpenBSD 7.2                    January 18, 2023                    OpenBSD 7.2
diff --git a/sshd_config.5 b/sshd_config.5
new file mode 100644
index 0000000..7313a7f
--- /dev/null
+++ b/sshd_config.5
@@ -0,0 +1,2082 @@
+.\"
+.\" Author: Tatu Ylonen <ylo@cs.hut.fi>
+.\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+.\"                    All rights reserved
+.\"
+.\" As far as I am concerned, the code I have written for this software
+.\" can be used freely for any purpose.  Any derived versions of this
+.\" software must be clearly marked as such, and if the derived work is
+.\" incompatible with the protocol description in the RFC file, it must be
+.\" called by a name other than "ssh" or "Secure Shell".
+.\"
+.\" Copyright (c) 1999,2000 Markus Friedl.  All rights reserved.
+.\" Copyright (c) 1999 Aaron Campbell.  All rights reserved.
+.\" Copyright (c) 1999 Theo de Raadt.  All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"
+.\" $OpenBSD: sshd_config.5,v 1.347 2023/01/18 06:55:32 jmc Exp $
+.Dd $Mdocdate: January 18 2023 $
+.Dt SSHD_CONFIG 5
+.Os
+.Sh NAME
+.Nm sshd_config
+.Nd OpenSSH daemon configuration file
+.Sh DESCRIPTION
+.Xr sshd 8
+reads configuration data from
+.Pa /etc/ssh/sshd_config
+(or the file specified with
+.Fl f
+on the command line).
+The file contains keyword-argument pairs, one per line.
+For each keyword, the first obtained value will be used.
+Lines starting with
+.Ql #
+and empty lines are interpreted as comments.
+Arguments may optionally be enclosed in double quotes
+.Pq \&"
+in order to represent arguments containing spaces.
+.Pp
+The possible
+keywords and their meanings are as follows (note that
+keywords are case-insensitive and arguments are case-sensitive):
+.Bl -tag -width Ds
+.It Cm AcceptEnv
+Specifies what environment variables sent by the client will be copied into
+the session's
+.Xr environ 7 .
+See
+.Cm SendEnv
+and
+.Cm SetEnv
+in
+.Xr ssh_config 5
+for how to configure the client.
+The
+.Ev TERM
+environment variable is always accepted whenever the client
+requests a pseudo-terminal as it is required by the protocol.
+Variables are specified by name, which may contain the wildcard characters
+.Ql *
+and
+.Ql \&? .
+Multiple environment variables may be separated by whitespace or spread
+across multiple
+.Cm AcceptEnv
+directives.
+Be warned that some environment variables could be used to bypass restricted
+user environments.
+For this reason, care should be taken in the use of this directive.
+The default is not to accept any environment variables.
+.It Cm AddressFamily
+Specifies which address family should be used by
+.Xr sshd 8 .
+Valid arguments are
+.Cm any
+(the default),
+.Cm inet
+(use IPv4 only), or
+.Cm inet6
+(use IPv6 only).
+.It Cm AllowAgentForwarding
+Specifies whether
+.Xr ssh-agent 1
+forwarding is permitted.
+The default is
+.Cm yes .
+Note that disabling agent forwarding does not improve security
+unless users are also denied shell access, as they can always install
+their own forwarders.
+.It Cm AllowGroups
+This keyword can be followed by a list of group name patterns, separated
+by spaces.
+If specified, login is allowed only for users whose primary
+group or supplementary group list matches one of the patterns.
+Only group names are valid; a numerical group ID is not recognized.
+By default, login is allowed for all groups.
+The allow/deny groups directives are processed in the following order:
+.Cm DenyGroups ,
+.Cm AllowGroups .
+.Pp
+See PATTERNS in
+.Xr ssh_config 5
+for more information on patterns.
+.It Cm AllowStreamLocalForwarding
+Specifies whether StreamLocal (Unix-domain socket) forwarding is permitted.
+The available options are
+.Cm yes
+(the default)
+or
+.Cm all
+to allow StreamLocal forwarding,
+.Cm no
+to prevent all StreamLocal forwarding,
+.Cm local
+to allow local (from the perspective of
+.Xr ssh 1 )
+forwarding only or
+.Cm remote
+to allow remote forwarding only.
+Note that disabling StreamLocal forwarding does not improve security unless
+users are also denied shell access, as they can always install their
+own forwarders.
+.It Cm AllowTcpForwarding
+Specifies whether TCP forwarding is permitted.
+The available options are
+.Cm yes
+(the default)
+or
+.Cm all
+to allow TCP forwarding,
+.Cm no
+to prevent all TCP forwarding,
+.Cm local
+to allow local (from the perspective of
+.Xr ssh 1 )
+forwarding only or
+.Cm remote
+to allow remote forwarding only.
+Note that disabling TCP forwarding does not improve security unless
+users are also denied shell access, as they can always install their
+own forwarders.
+.It Cm AllowUsers
+This keyword can be followed by a list of user name patterns, separated
+by spaces.
+If specified, login is allowed only for user names that
+match one of the patterns.
+Only user names are valid; a numerical user ID is not recognized.
+By default, login is allowed for all users.
+If the pattern takes the form USER@HOST then USER and HOST
+are separately checked, restricting logins to particular
+users from particular hosts.
+HOST criteria may additionally contain addresses to match in CIDR
+address/masklen format.
+The allow/deny users directives are processed in the following order:
+.Cm DenyUsers ,
+.Cm AllowUsers .
+.Pp
+See PATTERNS in
+.Xr ssh_config 5
+for more information on patterns.
+.It Cm AuthenticationMethods
+Specifies the authentication methods that must be successfully completed
+for a user to be granted access.
+This option must be followed by one or more lists of comma-separated
+authentication method names, or by the single string
+.Cm any
+to indicate the default behaviour of accepting any single authentication
+method.
+If the default is overridden, then successful authentication requires
+completion of every method in at least one of these lists.
+.Pp
+For example,
+.Qq publickey,password publickey,keyboard-interactive
+would require the user to complete public key authentication, followed by
+either password or keyboard interactive authentication.
+Only methods that are next in one or more lists are offered at each stage,
+so for this example it would not be possible to attempt password or
+keyboard-interactive authentication before public key.
+.Pp
+For keyboard interactive authentication it is also possible to
+restrict authentication to a specific device by appending a
+colon followed by the device identifier
+.Cm bsdauth
+or
+.Cm pam .
+depending on the server configuration.
+For example,
+.Qq keyboard-interactive:bsdauth
+would restrict keyboard interactive authentication to the
+.Cm bsdauth
+device.
+.Pp
+If the publickey method is listed more than once,
+.Xr sshd 8
+verifies that keys that have been used successfully are not reused for
+subsequent authentications.
+For example,
+.Qq publickey,publickey
+requires successful authentication using two different public keys.
+.Pp
+Note that each authentication method listed should also be explicitly enabled
+in the configuration.
+.Pp
+The available authentication methods are:
+.Qq gssapi-with-mic ,
+.Qq hostbased ,
+.Qq keyboard-interactive ,
+.Qq none
+(used for access to password-less accounts when
+.Cm PermitEmptyPasswords
+is enabled),
+.Qq password
+and
+.Qq publickey .
+.It Cm AuthorizedKeysCommand
+Specifies a program to be used to look up the user's public keys.
+The program must be owned by root, not writable by group or others and
+specified by an absolute path.
+Arguments to
+.Cm AuthorizedKeysCommand
+accept the tokens described in the
+.Sx TOKENS
+section.
+If no arguments are specified then the username of the target user is used.
+.Pp
+The program should produce on standard output zero or
+more lines of authorized_keys output (see
+.Sx AUTHORIZED_KEYS
+in
+.Xr sshd 8 ) .
+.Cm AuthorizedKeysCommand
+is tried after the usual
+.Cm AuthorizedKeysFile
+files and will not be executed if a matching key is found there.
+By default, no
+.Cm AuthorizedKeysCommand
+is run.
+.It Cm AuthorizedKeysCommandUser
+Specifies the user under whose account the
+.Cm AuthorizedKeysCommand
+is run.
+It is recommended to use a dedicated user that has no other role on the host
+than running authorized keys commands.
+If
+.Cm AuthorizedKeysCommand
+is specified but
+.Cm AuthorizedKeysCommandUser
+is not, then
+.Xr sshd 8
+will refuse to start.
+.It Cm AuthorizedKeysFile
+Specifies the file that contains the public keys used for user authentication.
+The format is described in the AUTHORIZED_KEYS FILE FORMAT section of
+.Xr sshd 8 .
+Arguments to
+.Cm AuthorizedKeysFile
+accept the tokens described in the
+.Sx TOKENS
+section.
+After expansion,
+.Cm AuthorizedKeysFile
+is taken to be an absolute path or one relative to the user's home
+directory.
+Multiple files may be listed, separated by whitespace.
+Alternately this option may be set to
+.Cm none
+to skip checking for user keys in files.
+The default is
+.Qq .ssh/authorized_keys .ssh/authorized_keys2 .
+.It Cm AuthorizedPrincipalsCommand
+Specifies a program to be used to generate the list of allowed
+certificate principals as per
+.Cm AuthorizedPrincipalsFile .
+The program must be owned by root, not writable by group or others and
+specified by an absolute path.
+Arguments to
+.Cm AuthorizedPrincipalsCommand
+accept the tokens described in the
+.Sx TOKENS
+section.
+If no arguments are specified then the username of the target user is used.
+.Pp
+The program should produce on standard output zero or
+more lines of
+.Cm AuthorizedPrincipalsFile
+output.
+If either
+.Cm AuthorizedPrincipalsCommand
+or
+.Cm AuthorizedPrincipalsFile
+is specified, then certificates offered by the client for authentication
+must contain a principal that is listed.
+By default, no
+.Cm AuthorizedPrincipalsCommand
+is run.
+.It Cm AuthorizedPrincipalsCommandUser
+Specifies the user under whose account the
+.Cm AuthorizedPrincipalsCommand
+is run.
+It is recommended to use a dedicated user that has no other role on the host
+than running authorized principals commands.
+If
+.Cm AuthorizedPrincipalsCommand
+is specified but
+.Cm AuthorizedPrincipalsCommandUser
+is not, then
+.Xr sshd 8
+will refuse to start.
+.It Cm AuthorizedPrincipalsFile
+Specifies a file that lists principal names that are accepted for
+certificate authentication.
+When using certificates signed by a key listed in
+.Cm TrustedUserCAKeys ,
+this file lists names, one of which must appear in the certificate for it
+to be accepted for authentication.
+Names are listed one per line preceded by key options (as described in
+.Sx AUTHORIZED_KEYS FILE FORMAT
+in
+.Xr sshd 8 ) .
+Empty lines and comments starting with
+.Ql #
+are ignored.
+.Pp
+Arguments to
+.Cm AuthorizedPrincipalsFile
+accept the tokens described in the
+.Sx TOKENS
+section.
+After expansion,
+.Cm AuthorizedPrincipalsFile
+is taken to be an absolute path or one relative to the user's home directory.
+The default is
+.Cm none ,
+i.e. not to use a principals file \(en in this case, the username
+of the user must appear in a certificate's principals list for it to be
+accepted.
+.Pp
+Note that
+.Cm AuthorizedPrincipalsFile
+is only used when authentication proceeds using a CA listed in
+.Cm TrustedUserCAKeys
+and is not consulted for certification authorities trusted via
+.Pa ~/.ssh/authorized_keys ,
+though the
+.Cm principals=
+key option offers a similar facility (see
+.Xr sshd 8
+for details).
+.It Cm Banner
+The contents of the specified file are sent to the remote user before
+authentication is allowed.
+If the argument is
+.Cm none
+then no banner is displayed.
+By default, no banner is displayed.
+.It Cm CASignatureAlgorithms
+Specifies which algorithms are allowed for signing of certificates
+by certificate authorities (CAs).
+The default is:
+.Bd -literal -offset indent
+ssh-ed25519,ecdsa-sha2-nistp256,
+ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
+sk-ssh-ed25519@openssh.com,
+sk-ecdsa-sha2-nistp256@openssh.com,
+rsa-sha2-512,rsa-sha2-256
+.Ed
+.Pp
+If the specified list begins with a
+.Sq +
+character, then the specified algorithms will be appended to the default set
+instead of replacing them.
+If the specified list begins with a
+.Sq -
+character, then the specified algorithms (including wildcards) will be removed
+from the default set instead of replacing them.
+.Pp
+Certificates signed using other algorithms will not be accepted for
+public key or host-based authentication.
+.It Cm ChannelTimeout
+Specifies whether and how quickly
+.Xr sshd 8
+should close inactive channels.
+Timeouts are specified as one or more
+.Dq type=interval
+pairs separated by whitespace, where the
+.Dq type
+must be a channel type name (as described in the table below), optionally
+containing wildcard characters.
+.Pp
+The timeout value
+.Dq interval
+is specified in seconds or may use any of the units documented in the
+.Sx TIME FORMATS
+section.
+For example,
+.Dq session:*=5m
+would cause all sessions to terminate after five minutes of inactivity.
+Specifying a zero value disables the inactivity timeout.
+.Pp
+The available channel types include:
+.Bl -tag -width Ds
+.It Cm agent-connection
+Open connections to
+.Xr ssh-agent 1 .
+.It Cm direct-tcpip , Cm direct-streamlocal@openssh.com
+Open TCP or Unix socket (respectively) connections that have
+been established from a
+.Xr ssh 1
+local forwarding, i.e.\&
+.Cm LocalForward
+or
+.Cm DynamicForward .
+.It Cm forwarded-tcpip , Cm forwarded-streamlocal@openssh.com
+Open TCP or Unix socket (respectively) connections that have been
+established to a
+.Xr sshd 8
+listening on behalf of a
+.Xr ssh 1
+remote forwarding, i.e.\&
+.Cm RemoteForward .
+.It Cm session:command
+Command execution sessions.
+.It Cm session:shell
+Interactive shell sessions.
+.It Cm session:subsystem:...
+Subsystem sessions, e.g. for
+.Xr sftp 1 ,
+which could be identified as
+.Cm session:subsystem:sftp .
+.It Cm x11-connection
+Open X11 forwarding sessions.
+.El
+.Pp
+Note that in all the above cases, terminating an inactive session does not
+guarantee to remove all resources associated with the session, e.g. shell
+processes or X11 clients relating to the session may continue to execute.
+.Pp
+Moreover, terminating an inactive channel or session does not necessarily
+close the SSH connection, nor does it prevent a client from
+requesting another channel of the same type.
+In particular, expiring an inactive forwarding session does not prevent
+another identical forwarding from being subsequently created.
+See also
+.Cm UnusedConnectionTimeout ,
+which may be used in conjunction with this option.
+.Pp
+The default is not to expire channels of any type for inactivity.
+.It Cm ChrootDirectory
+Specifies the pathname of a directory to
+.Xr chroot 2
+to after authentication.
+At session startup
+.Xr sshd 8
+checks that all components of the pathname are root-owned directories
+which are not writable by any other user or group.
+After the chroot,
+.Xr sshd 8
+changes the working directory to the user's home directory.
+Arguments to
+.Cm ChrootDirectory
+accept the tokens described in the
+.Sx TOKENS
+section.
+.Pp
+The
+.Cm ChrootDirectory
+must contain the necessary files and directories to support the
+user's session.
+For an interactive session this requires at least a shell, typically
+.Xr sh 1 ,
+and basic
+.Pa /dev
+nodes such as
+.Xr null 4 ,
+.Xr zero 4 ,
+.Xr stdin 4 ,
+.Xr stdout 4 ,
+.Xr stderr 4 ,
+and
+.Xr tty 4
+devices.
+For file transfer sessions using SFTP
+no additional configuration of the environment is necessary if the in-process
+sftp-server is used,
+though sessions which use logging may require
+.Pa /dev/log
+inside the chroot directory on some operating systems (see
+.Xr sftp-server 8
+for details).
+.Pp
+For safety, it is very important that the directory hierarchy be
+prevented from modification by other processes on the system (especially
+those outside the jail).
+Misconfiguration can lead to unsafe environments which
+.Xr sshd 8
+cannot detect.
+.Pp
+The default is
+.Cm none ,
+indicating not to
+.Xr chroot 2 .
+.It Cm Ciphers
+Specifies the ciphers allowed.
+Multiple ciphers must be comma-separated.
+If the specified list begins with a
+.Sq +
+character, then the specified ciphers will be appended to the default set
+instead of replacing them.
+If the specified list begins with a
+.Sq -
+character, then the specified ciphers (including wildcards) will be removed
+from the default set instead of replacing them.
+If the specified list begins with a
+.Sq ^
+character, then the specified ciphers will be placed at the head of the
+default set.
+.Pp
+The supported ciphers are:
+.Pp
+.Bl -item -compact -offset indent
+.It
+3des-cbc
+.It
+aes128-cbc
+.It
+aes192-cbc
+.It
+aes256-cbc
+.It
+aes128-ctr
+.It
+aes192-ctr
+.It
+aes256-ctr
+.It
+aes128-gcm@openssh.com
+.It
+aes256-gcm@openssh.com
+.It
+chacha20-poly1305@openssh.com
+.El
+.Pp
+The default is:
+.Bd -literal -offset indent
+chacha20-poly1305@openssh.com,
+aes128-ctr,aes192-ctr,aes256-ctr,
+aes128-gcm@openssh.com,aes256-gcm@openssh.com
+.Ed
+.Pp
+The list of available ciphers may also be obtained using
+.Qq ssh -Q cipher .
+.It Cm ClientAliveCountMax
+Sets the number of client alive messages which may be sent without
+.Xr sshd 8
+receiving any messages back from the client.
+If this threshold is reached while client alive messages are being sent,
+sshd will disconnect the client, terminating the session.
+It is important to note that the use of client alive messages is very
+different from
+.Cm TCPKeepAlive .
+The client alive messages are sent through the encrypted channel
+and therefore will not be spoofable.
+The TCP keepalive option enabled by
+.Cm TCPKeepAlive
+is spoofable.
+The client alive mechanism is valuable when the client or
+server depend on knowing when a connection has become unresponsive.
+.Pp
+The default value is 3.
+If
+.Cm ClientAliveInterval
+is set to 15, and
+.Cm ClientAliveCountMax
+is left at the default, unresponsive SSH clients
+will be disconnected after approximately 45 seconds.
+Setting a zero
+.Cm ClientAliveCountMax
+disables connection termination.
+.It Cm ClientAliveInterval
+Sets a timeout interval in seconds after which if no data has been received
+from the client,
+.Xr sshd 8
+will send a message through the encrypted
+channel to request a response from the client.
+The default
+is 0, indicating that these messages will not be sent to the client.
+.It Cm Compression
+Specifies whether compression is enabled after
+the user has authenticated successfully.
+The argument must be
+.Cm yes ,
+.Cm delayed
+(a legacy synonym for
+.Cm yes )
+or
+.Cm no .
+The default is
+.Cm yes .
+.It Cm DenyGroups
+This keyword can be followed by a list of group name patterns, separated
+by spaces.
+Login is disallowed for users whose primary group or supplementary
+group list matches one of the patterns.
+Only group names are valid; a numerical group ID is not recognized.
+By default, login is allowed for all groups.
+The allow/deny groups directives are processed in the following order:
+.Cm DenyGroups ,
+.Cm AllowGroups .
+.Pp
+See PATTERNS in
+.Xr ssh_config 5
+for more information on patterns.
+.It Cm DenyUsers
+This keyword can be followed by a list of user name patterns, separated
+by spaces.
+Login is disallowed for user names that match one of the patterns.
+Only user names are valid; a numerical user ID is not recognized.
+By default, login is allowed for all users.
+If the pattern takes the form USER@HOST then USER and HOST
+are separately checked, restricting logins to particular
+users from particular hosts.
+HOST criteria may additionally contain addresses to match in CIDR
+address/masklen format.
+The allow/deny users directives are processed in the following order:
+.Cm DenyUsers ,
+.Cm AllowUsers .
+.Pp
+See PATTERNS in
+.Xr ssh_config 5
+for more information on patterns.
+.It Cm DisableForwarding
+Disables all forwarding features, including X11,
+.Xr ssh-agent 1 ,
+TCP and StreamLocal.
+This option overrides all other forwarding-related options and may
+simplify restricted configurations.
+.It Cm ExposeAuthInfo
+Writes a temporary file containing a list of authentication methods and
+public credentials (e.g. keys) used to authenticate the user.
+The location of the file is exposed to the user session through the
+.Ev SSH_USER_AUTH
+environment variable.
+The default is
+.Cm no .
+.It Cm FingerprintHash
+Specifies the hash algorithm used when logging key fingerprints.
+Valid options are:
+.Cm md5
+and
+.Cm sha256 .
+The default is
+.Cm sha256 .
+.It Cm ForceCommand
+Forces the execution of the command specified by
+.Cm ForceCommand ,
+ignoring any command supplied by the client and
+.Pa ~/.ssh/rc
+if present.
+The command is invoked by using the user's login shell with the -c option.
+This applies to shell, command, or subsystem execution.
+It is most useful inside a
+.Cm Match
+block.
+The command originally supplied by the client is available in the
+.Ev SSH_ORIGINAL_COMMAND
+environment variable.
+Specifying a command of
+.Cm internal-sftp
+will force the use of an in-process SFTP server that requires no support
+files when used with
+.Cm ChrootDirectory .
+The default is
+.Cm none .
+.It Cm GatewayPorts
+Specifies whether remote hosts are allowed to connect to ports
+forwarded for the client.
+By default,
+.Xr sshd 8
+binds remote port forwardings to the loopback address.
+This prevents other remote hosts from connecting to forwarded ports.
+.Cm GatewayPorts
+can be used to specify that sshd
+should allow remote port forwardings to bind to non-loopback addresses, thus
+allowing other hosts to connect.
+The argument may be
+.Cm no
+to force remote port forwardings to be available to the local host only,
+.Cm yes
+to force remote port forwardings to bind to the wildcard address, or
+.Cm clientspecified
+to allow the client to select the address to which the forwarding is bound.
+The default is
+.Cm no .
+.It Cm GSSAPIAuthentication
+Specifies whether user authentication based on GSSAPI is allowed.
+The default is
+.Cm no .
+.It Cm GSSAPICleanupCredentials
+Specifies whether to automatically destroy the user's credentials cache
+on logout.
+The default is
+.Cm yes .
+.It Cm GSSAPIStrictAcceptorCheck
+Determines whether to be strict about the identity of the GSSAPI acceptor
+a client authenticates against.
+If set to
+.Cm yes
+then the client must authenticate against the host
+service on the current hostname.
+If set to
+.Cm no
+then the client may authenticate against any service key stored in the
+machine's default store.
+This facility is provided to assist with operation on multi homed machines.
+The default is
+.Cm yes .
+.It Cm HostbasedAcceptedAlgorithms
+Specifies the signature algorithms that will be accepted for hostbased
+authentication as a list of comma-separated patterns.
+Alternately if the specified list begins with a
+.Sq +
+character, then the specified signature algorithms will be appended to
+the default set instead of replacing them.
+If the specified list begins with a
+.Sq -
+character, then the specified signature algorithms (including wildcards)
+will be removed from the default set instead of replacing them.
+If the specified list begins with a
+.Sq ^
+character, then the specified signature algorithms will be placed at
+the head of the default set.
+The default for this option is:
+.Bd -literal -offset 3n
+ssh-ed25519-cert-v01@openssh.com,
+ecdsa-sha2-nistp256-cert-v01@openssh.com,
+ecdsa-sha2-nistp384-cert-v01@openssh.com,
+ecdsa-sha2-nistp521-cert-v01@openssh.com,
+sk-ssh-ed25519-cert-v01@openssh.com,
+sk-ecdsa-sha2-nistp256-cert-v01@openssh.com,
+rsa-sha2-512-cert-v01@openssh.com,
+rsa-sha2-256-cert-v01@openssh.com,
+ssh-ed25519,
+ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
+sk-ssh-ed25519@openssh.com,
+sk-ecdsa-sha2-nistp256@openssh.com,
+rsa-sha2-512,rsa-sha2-256
+.Ed
+.Pp
+The list of available signature algorithms may also be obtained using
+.Qq ssh -Q HostbasedAcceptedAlgorithms .
+This was formerly named HostbasedAcceptedKeyTypes.
+.It Cm HostbasedAuthentication
+Specifies whether rhosts or /etc/hosts.equiv authentication together
+with successful public key client host authentication is allowed
+(host-based authentication).
+The default is
+.Cm no .
+.It Cm HostbasedUsesNameFromPacketOnly
+Specifies whether or not the server will attempt to perform a reverse
+name lookup when matching the name in the
+.Pa ~/.shosts ,
+.Pa ~/.rhosts ,
+and
+.Pa /etc/hosts.equiv
+files during
+.Cm HostbasedAuthentication .
+A setting of
+.Cm yes
+means that
+.Xr sshd 8
+uses the name supplied by the client rather than
+attempting to resolve the name from the TCP connection itself.
+The default is
+.Cm no .
+.It Cm HostCertificate
+Specifies a file containing a public host certificate.
+The certificate's public key must match a private host key already specified
+by
+.Cm HostKey .
+The default behaviour of
+.Xr sshd 8
+is not to load any certificates.
+.It Cm HostKey
+Specifies a file containing a private host key
+used by SSH.
+The defaults are
+.Pa /etc/ssh/ssh_host_ecdsa_key ,
+.Pa /etc/ssh/ssh_host_ed25519_key
+and
+.Pa /etc/ssh/ssh_host_rsa_key .
+.Pp
+Note that
+.Xr sshd 8
+will refuse to use a file if it is group/world-accessible
+and that the
+.Cm HostKeyAlgorithms
+option restricts which of the keys are actually used by
+.Xr sshd 8 .
+.Pp
+It is possible to have multiple host key files.
+It is also possible to specify public host key files instead.
+In this case operations on the private key will be delegated
+to an
+.Xr ssh-agent 1 .
+.It Cm HostKeyAgent
+Identifies the UNIX-domain socket used to communicate
+with an agent that has access to the private host keys.
+If the string
+.Qq SSH_AUTH_SOCK
+is specified, the location of the socket will be read from the
+.Ev SSH_AUTH_SOCK
+environment variable.
+.It Cm HostKeyAlgorithms
+Specifies the host key signature algorithms
+that the server offers.
+The default for this option is:
+.Bd -literal -offset 3n
+ssh-ed25519-cert-v01@openssh.com,
+ecdsa-sha2-nistp256-cert-v01@openssh.com,
+ecdsa-sha2-nistp384-cert-v01@openssh.com,
+ecdsa-sha2-nistp521-cert-v01@openssh.com,
+sk-ssh-ed25519-cert-v01@openssh.com,
+sk-ecdsa-sha2-nistp256-cert-v01@openssh.com,
+rsa-sha2-512-cert-v01@openssh.com,
+rsa-sha2-256-cert-v01@openssh.com,
+ssh-ed25519,
+ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
+sk-ssh-ed25519@openssh.com,
+sk-ecdsa-sha2-nistp256@openssh.com,
+rsa-sha2-512,rsa-sha2-256
+.Ed
+.Pp
+The list of available signature algorithms may also be obtained using
+.Qq ssh -Q HostKeyAlgorithms .
+.It Cm IgnoreRhosts
+Specifies whether to ignore per-user
+.Pa .rhosts
+and
+.Pa .shosts
+files during
+.Cm HostbasedAuthentication .
+The system-wide
+.Pa /etc/hosts.equiv
+and
+.Pa /etc/shosts.equiv
+are still used regardless of this setting.
+.Pp
+Accepted values are
+.Cm yes
+(the default) to ignore all per-user files,
+.Cm shosts-only
+to allow the use of
+.Pa .shosts
+but to ignore
+.Pa .rhosts
+or
+.Cm no
+to allow both
+.Pa .shosts
+and
+.Pa rhosts .
+.It Cm IgnoreUserKnownHosts
+Specifies whether
+.Xr sshd 8
+should ignore the user's
+.Pa ~/.ssh/known_hosts
+during
+.Cm HostbasedAuthentication
+and use only the system-wide known hosts file
+.Pa /etc/ssh/ssh_known_hosts .
+The default is
+.Dq no .
+.It Cm Include
+Include the specified configuration file(s).
+Multiple pathnames may be specified and each pathname may contain
+.Xr glob 7
+wildcards that will be expanded and processed in lexical order.
+Files without absolute paths are assumed to be in
+.Pa /etc/ssh .
+An
+.Cm Include
+directive may appear inside a
+.Cm Match
+block
+to perform conditional inclusion.
+.It Cm IPQoS
+Specifies the IPv4 type-of-service or DSCP class for the connection.
+Accepted values are
+.Cm af11 ,
+.Cm af12 ,
+.Cm af13 ,
+.Cm af21 ,
+.Cm af22 ,
+.Cm af23 ,
+.Cm af31 ,
+.Cm af32 ,
+.Cm af33 ,
+.Cm af41 ,
+.Cm af42 ,
+.Cm af43 ,
+.Cm cs0 ,
+.Cm cs1 ,
+.Cm cs2 ,
+.Cm cs3 ,
+.Cm cs4 ,
+.Cm cs5 ,
+.Cm cs6 ,
+.Cm cs7 ,
+.Cm ef ,
+.Cm le ,
+.Cm lowdelay ,
+.Cm throughput ,
+.Cm reliability ,
+a numeric value, or
+.Cm none
+to use the operating system default.
+This option may take one or two arguments, separated by whitespace.
+If one argument is specified, it is used as the packet class unconditionally.
+If two values are specified, the first is automatically selected for
+interactive sessions and the second for non-interactive sessions.
+The default is
+.Cm af21
+(Low-Latency Data)
+for interactive sessions and
+.Cm cs1
+(Lower Effort)
+for non-interactive sessions.
+.It Cm KbdInteractiveAuthentication
+Specifies whether to allow keyboard-interactive authentication.
+All authentication styles from
+.Xr login.conf 5
+are supported.
+The default is
+.Cm yes .
+The argument to this keyword must be
+.Cm yes
+or
+.Cm no .
+.Cm ChallengeResponseAuthentication
+is a deprecated alias for this.
+.It Cm KerberosAuthentication
+Specifies whether the password provided by the user for
+.Cm PasswordAuthentication
+will be validated through the Kerberos KDC.
+To use this option, the server needs a
+Kerberos servtab which allows the verification of the KDC's identity.
+The default is
+.Cm no .
+.It Cm KerberosGetAFSToken
+If AFS is active and the user has a Kerberos 5 TGT, attempt to acquire
+an AFS token before accessing the user's home directory.
+The default is
+.Cm no .
+.It Cm KerberosOrLocalPasswd
+If password authentication through Kerberos fails then
+the password will be validated via any additional local mechanism
+such as
+.Pa /etc/passwd .
+The default is
+.Cm yes .
+.It Cm KerberosTicketCleanup
+Specifies whether to automatically destroy the user's ticket cache
+file on logout.
+The default is
+.Cm yes .
+.It Cm KexAlgorithms
+Specifies the available KEX (Key Exchange) algorithms.
+Multiple algorithms must be comma-separated.
+Alternately if the specified list begins with a
+.Sq +
+character, then the specified algorithms will be appended to the default set
+instead of replacing them.
+If the specified list begins with a
+.Sq -
+character, then the specified algorithms (including wildcards) will be removed
+from the default set instead of replacing them.
+If the specified list begins with a
+.Sq ^
+character, then the specified algorithms will be placed at the head of the
+default set.
+The supported algorithms are:
+.Pp
+.Bl -item -compact -offset indent
+.It
+curve25519-sha256
+.It
+curve25519-sha256@libssh.org
+.It
+diffie-hellman-group1-sha1
+.It
+diffie-hellman-group14-sha1
+.It
+diffie-hellman-group14-sha256
+.It
+diffie-hellman-group16-sha512
+.It
+diffie-hellman-group18-sha512
+.It
+diffie-hellman-group-exchange-sha1
+.It
+diffie-hellman-group-exchange-sha256
+.It
+ecdh-sha2-nistp256
+.It
+ecdh-sha2-nistp384
+.It
+ecdh-sha2-nistp521
+.It
+sntrup761x25519-sha512@openssh.com
+.El
+.Pp
+The default is:
+.Bd -literal -offset indent
+sntrup761x25519-sha512@openssh.com,
+curve25519-sha256,curve25519-sha256@libssh.org,
+ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,
+diffie-hellman-group-exchange-sha256,
+diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,
+diffie-hellman-group14-sha256
+.Ed
+.Pp
+The list of available key exchange algorithms may also be obtained using
+.Qq ssh -Q KexAlgorithms .
+.It Cm ListenAddress
+Specifies the local addresses
+.Xr sshd 8
+should listen on.
+The following forms may be used:
+.Pp
+.Bl -item -offset indent -compact
+.It
+.Cm ListenAddress
+.Sm off
+.Ar hostname | address
+.Sm on
+.Op Cm rdomain Ar domain
+.It
+.Cm ListenAddress
+.Sm off
+.Ar hostname : port
+.Sm on
+.Op Cm rdomain Ar domain
+.It
+.Cm ListenAddress
+.Sm off
+.Ar IPv4_address : port
+.Sm on
+.Op Cm rdomain Ar domain
+.It
+.Cm ListenAddress
+.Sm off
+.Oo Ar hostname | address Oc : Ar port
+.Sm on
+.Op Cm rdomain Ar domain
+.El
+.Pp
+The optional
+.Cm rdomain
+qualifier requests
+.Xr sshd 8
+listen in an explicit routing domain.
+If
+.Ar port
+is not specified,
+sshd will listen on the address and all
+.Cm Port
+options specified.
+The default is to listen on all local addresses on the current default
+routing domain.
+Multiple
+.Cm ListenAddress
+options are permitted.
+For more information on routing domains, see
+.Xr rdomain 4 .
+.It Cm LoginGraceTime
+The server disconnects after this time if the user has not
+successfully logged in.
+If the value is 0, there is no time limit.
+The default is 120 seconds.
+.It Cm LogLevel
+Gives the verbosity level that is used when logging messages from
+.Xr sshd 8 .
+The possible values are:
+QUIET, FATAL, ERROR, INFO, VERBOSE, DEBUG, DEBUG1, DEBUG2, and DEBUG3.
+The default is INFO.
+DEBUG and DEBUG1 are equivalent.
+DEBUG2 and DEBUG3 each specify higher levels of debugging output.
+Logging with a DEBUG level violates the privacy of users and is not recommended.
+.It Cm LogVerbose
+Specify one or more overrides to LogLevel.
+An override consists of a pattern lists that matches the source file, function
+and line number to force detailed logging for.
+For example, an override pattern of:
+.Bd -literal -offset indent
+kex.c:*:1000,*:kex_exchange_identification():*,packet.c:*
+.Ed
+.Pp
+would enable detailed logging for line 1000 of
+.Pa kex.c ,
+everything in the
+.Fn kex_exchange_identification
+function, and all code in the
+.Pa packet.c
+file.
+This option is intended for debugging and no overrides are enabled by default.
+.It Cm MACs
+Specifies the available MAC (message authentication code) algorithms.
+The MAC algorithm is used for data integrity protection.
+Multiple algorithms must be comma-separated.
+If the specified list begins with a
+.Sq +
+character, then the specified algorithms will be appended to the default set
+instead of replacing them.
+If the specified list begins with a
+.Sq -
+character, then the specified algorithms (including wildcards) will be removed
+from the default set instead of replacing them.
+If the specified list begins with a
+.Sq ^
+character, then the specified algorithms will be placed at the head of the
+default set.
+.Pp
+The algorithms that contain
+.Qq -etm
+calculate the MAC after encryption (encrypt-then-mac).
+These are considered safer and their use recommended.
+The supported MACs are:
+.Pp
+.Bl -item -compact -offset indent
+.It
+hmac-md5
+.It
+hmac-md5-96
+.It
+hmac-sha1
+.It
+hmac-sha1-96
+.It
+hmac-sha2-256
+.It
+hmac-sha2-512
+.It
+umac-64@openssh.com
+.It
+umac-128@openssh.com
+.It
+hmac-md5-etm@openssh.com
+.It
+hmac-md5-96-etm@openssh.com
+.It
+hmac-sha1-etm@openssh.com
+.It
+hmac-sha1-96-etm@openssh.com
+.It
+hmac-sha2-256-etm@openssh.com
+.It
+hmac-sha2-512-etm@openssh.com
+.It
+umac-64-etm@openssh.com
+.It
+umac-128-etm@openssh.com
+.El
+.Pp
+The default is:
+.Bd -literal -offset indent
+umac-64-etm@openssh.com,umac-128-etm@openssh.com,
+hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,
+hmac-sha1-etm@openssh.com,
+umac-64@openssh.com,umac-128@openssh.com,
+hmac-sha2-256,hmac-sha2-512,hmac-sha1
+.Ed
+.Pp
+The list of available MAC algorithms may also be obtained using
+.Qq ssh -Q mac .
+.It Cm Match
+Introduces a conditional block.
+If all of the criteria on the
+.Cm Match
+line are satisfied, the keywords on the following lines override those
+set in the global section of the config file, until either another
+.Cm Match
+line or the end of the file.
+If a keyword appears in multiple
+.Cm Match
+blocks that are satisfied, only the first instance of the keyword is
+applied.
+.Pp
+The arguments to
+.Cm Match
+are one or more criteria-pattern pairs or the single token
+.Cm All
+which matches all criteria.
+The available criteria are
+.Cm User ,
+.Cm Group ,
+.Cm Host ,
+.Cm LocalAddress ,
+.Cm LocalPort ,
+.Cm RDomain ,
+and
+.Cm Address
+(with
+.Cm RDomain
+representing the
+.Xr rdomain 4
+on which the connection was received).
+.Pp
+The match patterns may consist of single entries or comma-separated
+lists and may use the wildcard and negation operators described in the
+.Sx PATTERNS
+section of
+.Xr ssh_config 5 .
+.Pp
+The patterns in an
+.Cm Address
+criteria may additionally contain addresses to match in CIDR
+address/masklen format,
+such as 192.0.2.0/24 or 2001:db8::/32.
+Note that the mask length provided must be consistent with the address -
+it is an error to specify a mask length that is too long for the address
+or one with bits set in this host portion of the address.
+For example, 192.0.2.0/33 and 192.0.2.0/8, respectively.
+.Pp
+Only a subset of keywords may be used on the lines following a
+.Cm Match
+keyword.
+Available keywords are
+.Cm AcceptEnv ,
+.Cm AllowAgentForwarding ,
+.Cm AllowGroups ,
+.Cm AllowStreamLocalForwarding ,
+.Cm AllowTcpForwarding ,
+.Cm AllowUsers ,
+.Cm AuthenticationMethods ,
+.Cm AuthorizedKeysCommand ,
+.Cm AuthorizedKeysCommandUser ,
+.Cm AuthorizedKeysFile ,
+.Cm AuthorizedPrincipalsCommand ,
+.Cm AuthorizedPrincipalsCommandUser ,
+.Cm AuthorizedPrincipalsFile ,
+.Cm Banner ,
+.Cm CASignatureAlgorithms ,
+.Cm ChannelTimeout ,
+.Cm ChrootDirectory ,
+.Cm ClientAliveCountMax ,
+.Cm ClientAliveInterval ,
+.Cm DenyGroups ,
+.Cm DenyUsers ,
+.Cm DisableForwarding ,
+.Cm ExposeAuthInfo ,
+.Cm ForceCommand ,
+.Cm GatewayPorts ,
+.Cm GSSAPIAuthentication ,
+.Cm HostbasedAcceptedAlgorithms ,
+.Cm HostbasedAuthentication ,
+.Cm HostbasedUsesNameFromPacketOnly ,
+.Cm IgnoreRhosts ,
+.Cm Include ,
+.Cm IPQoS ,
+.Cm KbdInteractiveAuthentication ,
+.Cm KerberosAuthentication ,
+.Cm LogLevel ,
+.Cm MaxAuthTries ,
+.Cm MaxSessions ,
+.Cm PasswordAuthentication ,
+.Cm PermitEmptyPasswords ,
+.Cm PermitListen ,
+.Cm PermitOpen ,
+.Cm PermitRootLogin ,
+.Cm PermitTTY ,
+.Cm PermitTunnel ,
+.Cm PermitUserRC ,
+.Cm PubkeyAcceptedAlgorithms ,
+.Cm PubkeyAuthentication ,
+.Cm PubkeyAuthOptions ,
+.Cm RekeyLimit ,
+.Cm RevokedKeys ,
+.Cm RDomain ,
+.Cm SetEnv ,
+.Cm StreamLocalBindMask ,
+.Cm StreamLocalBindUnlink ,
+.Cm TrustedUserCAKeys ,
+.Cm UnusedConnectionTimeout ,
+.Cm X11DisplayOffset ,
+.Cm X11Forwarding
+and
+.Cm X11UseLocalhost .
+.It Cm MaxAuthTries
+Specifies the maximum number of authentication attempts permitted per
+connection.
+Once the number of failures reaches half this value,
+additional failures are logged.
+The default is 6.
+.It Cm MaxSessions
+Specifies the maximum number of open shell, login or subsystem (e.g. sftp)
+sessions permitted per network connection.
+Multiple sessions may be established by clients that support connection
+multiplexing.
+Setting
+.Cm MaxSessions
+to 1 will effectively disable session multiplexing, whereas setting it to 0
+will prevent all shell, login and subsystem sessions while still permitting
+forwarding.
+The default is 10.
+.It Cm MaxStartups
+Specifies the maximum number of concurrent unauthenticated connections to the
+SSH daemon.
+Additional connections will be dropped until authentication succeeds or the
+.Cm LoginGraceTime
+expires for a connection.
+The default is 10:30:100.
+.Pp
+Alternatively, random early drop can be enabled by specifying
+the three colon separated values
+start:rate:full (e.g. "10:30:60").
+.Xr sshd 8
+will refuse connection attempts with a probability of rate/100 (30%)
+if there are currently start (10) unauthenticated connections.
+The probability increases linearly and all connection attempts
+are refused if the number of unauthenticated connections reaches full (60).
+.It Cm ModuliFile
+Specifies the
+.Xr moduli 5
+file that contains the Diffie-Hellman groups used for the
+.Dq diffie-hellman-group-exchange-sha1
+and
+.Dq diffie-hellman-group-exchange-sha256
+key exchange methods.
+The default is
+.Pa /etc/moduli .
+.It Cm PasswordAuthentication
+Specifies whether password authentication is allowed.
+The default is
+.Cm yes .
+.It Cm PermitEmptyPasswords
+When password authentication is allowed, it specifies whether the
+server allows login to accounts with empty password strings.
+The default is
+.Cm no .
+.It Cm PermitListen
+Specifies the addresses/ports on which a remote TCP port forwarding may listen.
+The listen specification must be one of the following forms:
+.Pp
+.Bl -item -offset indent -compact
+.It
+.Cm PermitListen
+.Sm off
+.Ar port
+.Sm on
+.It
+.Cm PermitListen
+.Sm off
+.Ar host : port
+.Sm on
+.El
+.Pp
+Multiple permissions may be specified by separating them with whitespace.
+An argument of
+.Cm any
+can be used to remove all restrictions and permit any listen requests.
+An argument of
+.Cm none
+can be used to prohibit all listen requests.
+The host name may contain wildcards as described in the PATTERNS section in
+.Xr ssh_config 5 .
+The wildcard
+.Sq *
+can also be used in place of a port number to allow all ports.
+By default all port forwarding listen requests are permitted.
+Note that the
+.Cm GatewayPorts
+option may further restrict which addresses may be listened on.
+Note also that
+.Xr ssh 1
+will request a listen host of
+.Dq localhost
+if no listen host was specifically requested, and this name is
+treated differently to explicit localhost addresses of
+.Dq 127.0.0.1
+and
+.Dq ::1 .
+.It Cm PermitOpen
+Specifies the destinations to which TCP port forwarding is permitted.
+The forwarding specification must be one of the following forms:
+.Pp
+.Bl -item -offset indent -compact
+.It
+.Cm PermitOpen
+.Sm off
+.Ar host : port
+.Sm on
+.It
+.Cm PermitOpen
+.Sm off
+.Ar IPv4_addr : port
+.Sm on
+.It
+.Cm PermitOpen
+.Sm off
+.Ar \&[ IPv6_addr \&] : port
+.Sm on
+.El
+.Pp
+Multiple forwards may be specified by separating them with whitespace.
+An argument of
+.Cm any
+can be used to remove all restrictions and permit any forwarding requests.
+An argument of
+.Cm none
+can be used to prohibit all forwarding requests.
+The wildcard
+.Sq *
+can be used for host or port to allow all hosts or ports respectively.
+Otherwise, no pattern matching or address lookups are performed on supplied
+names.
+By default all port forwarding requests are permitted.
+.It Cm PermitRootLogin
+Specifies whether root can log in using
+.Xr ssh 1 .
+The argument must be
+.Cm yes ,
+.Cm prohibit-password ,
+.Cm forced-commands-only ,
+or
+.Cm no .
+The default is
+.Cm prohibit-password .
+.Pp
+If this option is set to
+.Cm prohibit-password
+(or its deprecated alias,
+.Cm without-password ) ,
+password and keyboard-interactive authentication are disabled for root.
+.Pp
+If this option is set to
+.Cm forced-commands-only ,
+root login with public key authentication will be allowed,
+but only if the
+.Ar command
+option has been specified
+(which may be useful for taking remote backups even if root login is
+normally not allowed).
+All other authentication methods are disabled for root.
+.Pp
+If this option is set to
+.Cm no ,
+root is not allowed to log in.
+.It Cm PermitTTY
+Specifies whether
+.Xr pty 4
+allocation is permitted.
+The default is
+.Cm yes .
+.It Cm PermitTunnel
+Specifies whether
+.Xr tun 4
+device forwarding is allowed.
+The argument must be
+.Cm yes ,
+.Cm point-to-point
+(layer 3),
+.Cm ethernet
+(layer 2), or
+.Cm no .
+Specifying
+.Cm yes
+permits both
+.Cm point-to-point
+and
+.Cm ethernet .
+The default is
+.Cm no .
+.Pp
+Independent of this setting, the permissions of the selected
+.Xr tun 4
+device must allow access to the user.
+.It Cm PermitUserEnvironment
+Specifies whether
+.Pa ~/.ssh/environment
+and
+.Cm environment=
+options in
+.Pa ~/.ssh/authorized_keys
+are processed by
+.Xr sshd 8 .
+Valid options are
+.Cm yes ,
+.Cm no
+or a pattern-list specifying which environment variable names to accept
+(for example
+.Qq LANG,LC_* ) .
+The default is
+.Cm no .
+Enabling environment processing may enable users to bypass access
+restrictions in some configurations using mechanisms such as
+.Ev LD_PRELOAD .
+.It Cm PermitUserRC
+Specifies whether any
+.Pa ~/.ssh/rc
+file is executed.
+The default is
+.Cm yes .
+.It Cm PerSourceMaxStartups
+Specifies the number of unauthenticated connections allowed from a
+given source address, or
+.Dq none
+if there is no limit.
+This limit is applied in addition to
+.Cm MaxStartups ,
+whichever is lower.
+The default is
+.Cm none .
+.It Cm PerSourceNetBlockSize
+Specifies the number of bits of source address that are grouped together
+for the purposes of applying PerSourceMaxStartups limits.
+Values for IPv4 and optionally IPv6 may be specified, separated by a colon.
+The default is
+.Cm 32:128 ,
+which means each address is considered individually.
+.It Cm PidFile
+Specifies the file that contains the process ID of the
+SSH daemon, or
+.Cm none
+to not write one.
+The default is
+.Pa /var/run/sshd.pid .
+.It Cm Port
+Specifies the port number that
+.Xr sshd 8
+listens on.
+The default is 22.
+Multiple options of this type are permitted.
+See also
+.Cm ListenAddress .
+.It Cm PrintLastLog
+Specifies whether
+.Xr sshd 8
+should print the date and time of the last user login when a user logs
+in interactively.
+The default is
+.Cm yes .
+.It Cm PrintMotd
+Specifies whether
+.Xr sshd 8
+should print
+.Pa /etc/motd
+when a user logs in interactively.
+(On some systems it is also printed by the shell,
+.Pa /etc/profile ,
+or equivalent.)
+The default is
+.Cm yes .
+.It Cm PubkeyAcceptedAlgorithms
+Specifies the signature algorithms that will be accepted for public key
+authentication as a list of comma-separated patterns.
+Alternately if the specified list begins with a
+.Sq +
+character, then the specified algorithms will be appended to the default set
+instead of replacing them.
+If the specified list begins with a
+.Sq -
+character, then the specified algorithms (including wildcards) will be removed
+from the default set instead of replacing them.
+If the specified list begins with a
+.Sq ^
+character, then the specified algorithms will be placed at the head of the
+default set.
+The default for this option is:
+.Bd -literal -offset 3n
+ssh-ed25519-cert-v01@openssh.com,
+ecdsa-sha2-nistp256-cert-v01@openssh.com,
+ecdsa-sha2-nistp384-cert-v01@openssh.com,
+ecdsa-sha2-nistp521-cert-v01@openssh.com,
+sk-ssh-ed25519-cert-v01@openssh.com,
+sk-ecdsa-sha2-nistp256-cert-v01@openssh.com,
+rsa-sha2-512-cert-v01@openssh.com,
+rsa-sha2-256-cert-v01@openssh.com,
+ssh-ed25519,
+ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
+sk-ssh-ed25519@openssh.com,
+sk-ecdsa-sha2-nistp256@openssh.com,
+rsa-sha2-512,rsa-sha2-256
+.Ed
+.Pp
+The list of available signature algorithms may also be obtained using
+.Qq ssh -Q PubkeyAcceptedAlgorithms .
+.It Cm PubkeyAuthOptions
+Sets one or more public key authentication options.
+The supported keywords are:
+.Cm none
+(the default; indicating no additional options are enabled),
+.Cm touch-required
+and
+.Cm verify-required .
+.Pp
+The
+.Cm touch-required
+option causes public key authentication using a FIDO authenticator algorithm
+(i.e.\&
+.Cm ecdsa-sk
+or
+.Cm ed25519-sk )
+to always require the signature to attest that a physically present user
+explicitly confirmed the authentication (usually by touching the authenticator).
+By default,
+.Xr sshd 8
+requires user presence unless overridden with an authorized_keys option.
+The
+.Cm touch-required
+flag disables this override.
+.Pp
+The
+.Cm verify-required
+option requires a FIDO key signature attest that the user was verified,
+e.g. via a PIN.
+.Pp
+Neither the
+.Cm touch-required
+or
+.Cm verify-required
+options have any effect for other, non-FIDO, public key types.
+.It Cm PubkeyAuthentication
+Specifies whether public key authentication is allowed.
+The default is
+.Cm yes .
+.It Cm RekeyLimit
+Specifies the maximum amount of data that may be transmitted or received
+before the session key is renegotiated, optionally followed by a maximum
+amount of time that may pass before the session key is renegotiated.
+The first argument is specified in bytes and may have a suffix of
+.Sq K ,
+.Sq M ,
+or
+.Sq G
+to indicate Kilobytes, Megabytes, or Gigabytes, respectively.
+The default is between
+.Sq 1G
+and
+.Sq 4G ,
+depending on the cipher.
+The optional second value is specified in seconds and may use any of the
+units documented in the
+.Sx TIME FORMATS
+section.
+The default value for
+.Cm RekeyLimit
+is
+.Cm default none ,
+which means that rekeying is performed after the cipher's default amount
+of data has been sent or received and no time based rekeying is done.
+.It Cm RequiredRSASize
+Specifies the minimum RSA key size (in bits) that
+.Xr sshd 8
+will accept.
+User and host-based authentication keys smaller than this limit will be
+refused.
+The default is
+.Cm 1024
+bits.
+Note that this limit may only be raised from the default.
+.It Cm RevokedKeys
+Specifies revoked public keys file, or
+.Cm none
+to not use one.
+Keys listed in this file will be refused for public key authentication.
+Note that if this file is not readable, then public key authentication will
+be refused for all users.
+Keys may be specified as a text file, listing one public key per line, or as
+an OpenSSH Key Revocation List (KRL) as generated by
+.Xr ssh-keygen 1 .
+For more information on KRLs, see the KEY REVOCATION LISTS section in
+.Xr ssh-keygen 1 .
+.It Cm RDomain
+Specifies an explicit routing domain that is applied after authentication
+has completed.
+The user session, as well as any forwarded or listening IP sockets,
+will be bound to this
+.Xr rdomain 4 .
+If the routing domain is set to
+.Cm \&%D ,
+then the domain in which the incoming connection was received will be applied.
+.It Cm SecurityKeyProvider
+Specifies a path to a library that will be used when loading
+FIDO authenticator-hosted keys, overriding the default of using
+the built-in USB HID support.
+.It Cm SetEnv
+Specifies one or more environment variables to set in child sessions started
+by
+.Xr sshd 8
+as
+.Dq NAME=VALUE .
+The environment value may be quoted (e.g. if it contains whitespace
+characters).
+Environment variables set by
+.Cm SetEnv
+override the default environment and any variables specified by the user
+via
+.Cm AcceptEnv
+or
+.Cm PermitUserEnvironment .
+.It Cm StreamLocalBindMask
+Sets the octal file creation mode mask
+.Pq umask
+used when creating a Unix-domain socket file for local or remote
+port forwarding.
+This option is only used for port forwarding to a Unix-domain socket file.
+.Pp
+The default value is 0177, which creates a Unix-domain socket file that is
+readable and writable only by the owner.
+Note that not all operating systems honor the file mode on Unix-domain
+socket files.
+.It Cm StreamLocalBindUnlink
+Specifies whether to remove an existing Unix-domain socket file for local
+or remote port forwarding before creating a new one.
+If the socket file already exists and
+.Cm StreamLocalBindUnlink
+is not enabled,
+.Nm sshd
+will be unable to forward the port to the Unix-domain socket file.
+This option is only used for port forwarding to a Unix-domain socket file.
+.Pp
+The argument must be
+.Cm yes
+or
+.Cm no .
+The default is
+.Cm no .
+.It Cm StrictModes
+Specifies whether
+.Xr sshd 8
+should check file modes and ownership of the
+user's files and home directory before accepting login.
+This is normally desirable because novices sometimes accidentally leave their
+directory or files world-writable.
+The default is
+.Cm yes .
+Note that this does not apply to
+.Cm ChrootDirectory ,
+whose permissions and ownership are checked unconditionally.
+.It Cm Subsystem
+Configures an external subsystem (e.g. file transfer daemon).
+Arguments should be a subsystem name and a command (with optional arguments)
+to execute upon subsystem request.
+.Pp
+The command
+.Cm sftp-server
+implements the SFTP file transfer subsystem.
+.Pp
+Alternately the name
+.Cm internal-sftp
+implements an in-process SFTP server.
+This may simplify configurations using
+.Cm ChrootDirectory
+to force a different filesystem root on clients.
+.Pp
+By default no subsystems are defined.
+.It Cm SyslogFacility
+Gives the facility code that is used when logging messages from
+.Xr sshd 8 .
+The possible values are: DAEMON, USER, AUTH, LOCAL0, LOCAL1, LOCAL2,
+LOCAL3, LOCAL4, LOCAL5, LOCAL6, LOCAL7.
+The default is AUTH.
+.It Cm TCPKeepAlive
+Specifies whether the system should send TCP keepalive messages to the
+other side.
+If they are sent, death of the connection or crash of one
+of the machines will be properly noticed.
+However, this means that
+connections will die if the route is down temporarily, and some people
+find it annoying.
+On the other hand, if TCP keepalives are not sent,
+sessions may hang indefinitely on the server, leaving
+.Qq ghost
+users and consuming server resources.
+.Pp
+The default is
+.Cm yes
+(to send TCP keepalive messages), and the server will notice
+if the network goes down or the client host crashes.
+This avoids infinitely hanging sessions.
+.Pp
+To disable TCP keepalive messages, the value should be set to
+.Cm no .
+.It Cm TrustedUserCAKeys
+Specifies a file containing public keys of certificate authorities that are
+trusted to sign user certificates for authentication, or
+.Cm none
+to not use one.
+Keys are listed one per line; empty lines and comments starting with
+.Ql #
+are allowed.
+If a certificate is presented for authentication and has its signing CA key
+listed in this file, then it may be used for authentication for any user
+listed in the certificate's principals list.
+Note that certificates that lack a list of principals will not be permitted
+for authentication using
+.Cm TrustedUserCAKeys .
+For more details on certificates, see the CERTIFICATES section in
+.Xr ssh-keygen 1 .
+.It Cm UnusedConnectionTimeout
+Specifies whether and how quickly
+.Xr sshd 8
+should close client connections with no open channels.
+Open channels include active shell, command execution or subsystem
+sessions, connected network, socket, agent or X11 forwardings.
+Forwarding listeners, such as those from the
+.Xr ssh 1
+.Fl R
+flag, are not considered as open channels and do not prevent the timeout.
+The timeout value
+is specified in seconds or may use any of the units documented in the
+.Sx TIME FORMATS
+section.
+.Pp
+Note that this timeout starts when the client connection completes
+user authentication but before the client has an opportunity to open any
+channels.
+Caution should be used when using short timeout values, as they may not
+provide sufficient time for the client to request and open its channels
+before terminating the connection.
+.Pp
+The default
+.Cm none
+is to never expire connections for having no open channels.
+This option may be useful in conjunction with
+.Cm ChannelTimeout .
+.It Cm UseDNS
+Specifies whether
+.Xr sshd 8
+should look up the remote host name, and to check that
+the resolved host name for the remote IP address maps back to the
+very same IP address.
+.Pp
+If this option is set to
+.Cm no
+(the default) then only addresses and not host names may be used in
+.Pa ~/.ssh/authorized_keys
+.Cm from
+and
+.Nm
+.Cm Match
+.Cm Host
+directives.
+.It Cm UsePAM
+Enables the Pluggable Authentication Module interface.
+If set to
+.Cm yes
+this will enable PAM authentication using
+.Cm KbdInteractiveAuthentication
+and
+.Cm PasswordAuthentication
+in addition to PAM account and session module processing for all
+authentication types.
+.Pp
+Because PAM keyboard-interactive authentication usually serves an equivalent
+role to password authentication, you should disable either
+.Cm PasswordAuthentication
+or
+.Cm KbdInteractiveAuthentication .
+.Pp
+If
+.Cm UsePAM
+is enabled, you will not be able to run
+.Xr sshd 8
+as a non-root user.
+The default is
+.Cm no .
+.It Cm VersionAddendum
+Optionally specifies additional text to append to the SSH protocol banner
+sent by the server upon connection.
+The default is
+.Cm none .
+.It Cm X11DisplayOffset
+Specifies the first display number available for
+.Xr sshd 8 Ns 's
+X11 forwarding.
+This prevents sshd from interfering with real X11 servers.
+The default is 10.
+.It Cm X11Forwarding
+Specifies whether X11 forwarding is permitted.
+The argument must be
+.Cm yes
+or
+.Cm no .
+The default is
+.Cm no .
+.Pp
+When X11 forwarding is enabled, there may be additional exposure to
+the server and to client displays if the
+.Xr sshd 8
+proxy display is configured to listen on the wildcard address (see
+.Cm X11UseLocalhost ) ,
+though this is not the default.
+Additionally, the authentication spoofing and authentication data
+verification and substitution occur on the client side.
+The security risk of using X11 forwarding is that the client's X11
+display server may be exposed to attack when the SSH client requests
+forwarding (see the warnings for
+.Cm ForwardX11
+in
+.Xr ssh_config 5 ) .
+A system administrator may have a stance in which they want to
+protect clients that may expose themselves to attack by unwittingly
+requesting X11 forwarding, which can warrant a
+.Cm no
+setting.
+.Pp
+Note that disabling X11 forwarding does not prevent users from
+forwarding X11 traffic, as users can always install their own forwarders.
+.It Cm X11UseLocalhost
+Specifies whether
+.Xr sshd 8
+should bind the X11 forwarding server to the loopback address or to
+the wildcard address.
+By default,
+sshd binds the forwarding server to the loopback address and sets the
+hostname part of the
+.Ev DISPLAY
+environment variable to
+.Cm localhost .
+This prevents remote hosts from connecting to the proxy display.
+However, some older X11 clients may not function with this
+configuration.
+.Cm X11UseLocalhost
+may be set to
+.Cm no
+to specify that the forwarding server should be bound to the wildcard
+address.
+The argument must be
+.Cm yes
+or
+.Cm no .
+The default is
+.Cm yes .
+.It Cm XAuthLocation
+Specifies the full pathname of the
+.Xr xauth 1
+program, or
+.Cm none
+to not use one.
+The default is
+.Pa /usr/X11R6/bin/xauth .
+.El
+.Sh TIME FORMATS
+.Xr sshd 8
+command-line arguments and configuration file options that specify time
+may be expressed using a sequence of the form:
+.Sm off
+.Ar time Op Ar qualifier ,
+.Sm on
+where
+.Ar time
+is a positive integer value and
+.Ar qualifier
+is one of the following:
+.Pp
+.Bl -tag -width Ds -compact -offset indent
+.It Aq Cm none
+seconds
+.It Cm s | Cm S
+seconds
+.It Cm m | Cm M
+minutes
+.It Cm h | Cm H
+hours
+.It Cm d | Cm D
+days
+.It Cm w | Cm W
+weeks
+.El
+.Pp
+Each member of the sequence is added together to calculate
+the total time value.
+.Pp
+Time format examples:
+.Pp
+.Bl -tag -width Ds -compact -offset indent
+.It 600
+600 seconds (10 minutes)
+.It 10m
+10 minutes
+.It 1h30m
+1 hour 30 minutes (90 minutes)
+.El
+.Sh TOKENS
+Arguments to some keywords can make use of tokens,
+which are expanded at runtime:
+.Pp
+.Bl -tag -width XXXX -offset indent -compact
+.It %%
+A literal
+.Sq % .
+.It \&%D
+The routing domain in which the incoming connection was received.
+.It %F
+The fingerprint of the CA key.
+.It %f
+The fingerprint of the key or certificate.
+.It %h
+The home directory of the user.
+.It %i
+The key ID in the certificate.
+.It %K
+The base64-encoded CA key.
+.It %k
+The base64-encoded key or certificate for authentication.
+.It %s
+The serial number of the certificate.
+.It \&%T
+The type of the CA key.
+.It %t
+The key or certificate type.
+.It \&%U
+The numeric user ID of the target user.
+.It %u
+The username.
+.El
+.Pp
+.Cm AuthorizedKeysCommand
+accepts the tokens %%, %f, %h, %k, %t, %U, and %u.
+.Pp
+.Cm AuthorizedKeysFile
+accepts the tokens %%, %h, %U, and %u.
+.Pp
+.Cm AuthorizedPrincipalsCommand
+accepts the tokens %%, %F, %f, %h, %i, %K, %k, %s, %T, %t, %U, and %u.
+.Pp
+.Cm AuthorizedPrincipalsFile
+accepts the tokens %%, %h, %U, and %u.
+.Pp
+.Cm ChrootDirectory
+accepts the tokens %%, %h, %U, and %u.
+.Pp
+.Cm RoutingDomain
+accepts the token %D.
+.Sh FILES
+.Bl -tag -width Ds
+.It Pa /etc/ssh/sshd_config
+Contains configuration data for
+.Xr sshd 8 .
+This file should be writable by root only, but it is recommended
+(though not necessary) that it be world-readable.
+.El
+.Sh SEE ALSO
+.Xr sftp-server 8 ,
+.Xr sshd 8
+.Sh AUTHORS
+.An -nosplit
+OpenSSH is a derivative of the original and free
+ssh 1.2.12 release by
+.An Tatu Ylonen .
+.An Aaron Campbell , Bob Beck , Markus Friedl , Niels Provos ,
+.An Theo de Raadt
+and
+.An Dug Song
+removed many bugs, re-added newer features and
+created OpenSSH.
+.An Markus Friedl
+contributed the support for SSH protocol versions 1.5 and 2.0.
+.An Niels Provos
+and
+.An Markus Friedl
+contributed support for privilege separation.