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<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>21.1. The pg_hba.conf File</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="client-authentication.html" title="Chapter 21. Client Authentication" /><link rel="next" href="auth-username-maps.html" title="21.2. User Name Maps" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">21.1. The <code class="filename">pg_hba.conf</code> File</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="client-authentication.html" title="Chapter 21. Client Authentication">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="client-authentication.html" title="Chapter 21. Client Authentication">Up</a></td><th width="60%" align="center">Chapter 21. Client Authentication</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 15.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="auth-username-maps.html" title="21.2. User Name Maps">Next</a></td></tr></table><hr /></div><div class="sect1" id="AUTH-PG-HBA-CONF"><div class="titlepage"><div><div><h2 class="title" style="clear: both">21.1. The <code class="filename">pg_hba.conf</code> File</h2></div></div></div><a id="id-1.6.8.8.2" class="indexterm"></a><p>
Client authentication is controlled by a configuration file,
which traditionally is named
<code class="filename">pg_hba.conf</code> and is stored in the database
cluster's data directory.
(<acronym class="acronym">HBA</acronym> stands for host-based authentication.) A default
<code class="filename">pg_hba.conf</code> file is installed when the data
directory is initialized by <a class="xref" href="app-initdb.html" title="initdb"><span class="refentrytitle"><span class="application">initdb</span></span></a>. It is
possible to place the authentication configuration file elsewhere,
however; see the <a class="xref" href="runtime-config-file-locations.html#GUC-HBA-FILE">hba_file</a> configuration parameter.
</p><p>
The general format of the <code class="filename">pg_hba.conf</code> file is
a set of records, one per line. Blank lines are ignored, as is any
text after the <code class="literal">#</code> comment character.
A record can be continued onto the next line by ending the line with
a backslash. (Backslashes are not special except at the end of a line.)
A record is made
up of a number of fields which are separated by spaces and/or tabs.
Fields can contain white space if the field value is double-quoted.
Quoting one of the keywords in a database, user, or address field (e.g.,
<code class="literal">all</code> or <code class="literal">replication</code>) makes the word lose its special
meaning, and just match a database, user, or host with that name.
Backslash line continuation applies even within quoted text or comments.
</p><p>
Each record specifies a connection type, a client IP address range
(if relevant for the connection type), a database name, a user name,
and the authentication method to be used for connections matching
these parameters. The first record with a matching connection type,
client address, requested database, and user name is used to perform
authentication. There is no <span class="quote">“<span class="quote">fall-through</span>”</span> or
<span class="quote">“<span class="quote">backup</span>”</span>: if one record is chosen and the authentication
fails, subsequent records are not considered. If no record matches,
access is denied.
</p><p>
A record can have several formats:
</p><pre class="synopsis">
local <em class="replaceable"><code>database</code></em> <em class="replaceable"><code>user</code></em> <em class="replaceable"><code>auth-method</code></em> [<span class="optional"><em class="replaceable"><code>auth-options</code></em></span>]
host <em class="replaceable"><code>database</code></em> <em class="replaceable"><code>user</code></em> <em class="replaceable"><code>address</code></em> <em class="replaceable"><code>auth-method</code></em> [<span class="optional"><em class="replaceable"><code>auth-options</code></em></span>]
hostssl <em class="replaceable"><code>database</code></em> <em class="replaceable"><code>user</code></em> <em class="replaceable"><code>address</code></em> <em class="replaceable"><code>auth-method</code></em> [<span class="optional"><em class="replaceable"><code>auth-options</code></em></span>]
hostnossl <em class="replaceable"><code>database</code></em> <em class="replaceable"><code>user</code></em> <em class="replaceable"><code>address</code></em> <em class="replaceable"><code>auth-method</code></em> [<span class="optional"><em class="replaceable"><code>auth-options</code></em></span>]
hostgssenc <em class="replaceable"><code>database</code></em> <em class="replaceable"><code>user</code></em> <em class="replaceable"><code>address</code></em> <em class="replaceable"><code>auth-method</code></em> [<span class="optional"><em class="replaceable"><code>auth-options</code></em></span>]
hostnogssenc <em class="replaceable"><code>database</code></em> <em class="replaceable"><code>user</code></em> <em class="replaceable"><code>address</code></em> <em class="replaceable"><code>auth-method</code></em> [<span class="optional"><em class="replaceable"><code>auth-options</code></em></span>]
host <em class="replaceable"><code>database</code></em> <em class="replaceable"><code>user</code></em> <em class="replaceable"><code>IP-address</code></em> <em class="replaceable"><code>IP-mask</code></em> <em class="replaceable"><code>auth-method</code></em> [<span class="optional"><em class="replaceable"><code>auth-options</code></em></span>]
hostssl <em class="replaceable"><code>database</code></em> <em class="replaceable"><code>user</code></em> <em class="replaceable"><code>IP-address</code></em> <em class="replaceable"><code>IP-mask</code></em> <em class="replaceable"><code>auth-method</code></em> [<span class="optional"><em class="replaceable"><code>auth-options</code></em></span>]
hostnossl <em class="replaceable"><code>database</code></em> <em class="replaceable"><code>user</code></em> <em class="replaceable"><code>IP-address</code></em> <em class="replaceable"><code>IP-mask</code></em> <em class="replaceable"><code>auth-method</code></em> [<span class="optional"><em class="replaceable"><code>auth-options</code></em></span>]
hostgssenc <em class="replaceable"><code>database</code></em> <em class="replaceable"><code>user</code></em> <em class="replaceable"><code>IP-address</code></em> <em class="replaceable"><code>IP-mask</code></em> <em class="replaceable"><code>auth-method</code></em> [<span class="optional"><em class="replaceable"><code>auth-options</code></em></span>]
hostnogssenc <em class="replaceable"><code>database</code></em> <em class="replaceable"><code>user</code></em> <em class="replaceable"><code>IP-address</code></em> <em class="replaceable"><code>IP-mask</code></em> <em class="replaceable"><code>auth-method</code></em> [<span class="optional"><em class="replaceable"><code>auth-options</code></em></span>]
</pre><p>
The meaning of the fields is as follows:
</p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">local</code></span></dt><dd><p>
This record matches connection attempts using Unix-domain
sockets. Without a record of this type, Unix-domain socket
connections are disallowed.
</p></dd><dt><span class="term"><code class="literal">host</code></span></dt><dd><p>
This record matches connection attempts made using TCP/IP.
<code class="literal">host</code> records match
<acronym class="acronym">SSL</acronym> or non-<acronym class="acronym">SSL</acronym> connection
attempts as well as <acronym class="acronym">GSSAPI</acronym> encrypted or
non-<acronym class="acronym">GSSAPI</acronym> encrypted connection attempts.
</p><div class="note"><h3 class="title">Note</h3><p>
Remote TCP/IP connections will not be possible unless
the server is started with an appropriate value for the
<a class="xref" href="runtime-config-connection.html#GUC-LISTEN-ADDRESSES">listen_addresses</a> configuration parameter,
since the default behavior is to listen for TCP/IP connections
only on the local loopback address <code class="literal">localhost</code>.
</p></div></dd><dt><span class="term"><code class="literal">hostssl</code></span></dt><dd><p>
This record matches connection attempts made using TCP/IP,
but only when the connection is made with <acronym class="acronym">SSL</acronym>
encryption.
</p><p>
To make use of this option the server must be built with
<acronym class="acronym">SSL</acronym> support. Furthermore,
<acronym class="acronym">SSL</acronym> must be enabled
by setting the <a class="xref" href="runtime-config-connection.html#GUC-SSL">ssl</a> configuration parameter (see
<a class="xref" href="ssl-tcp.html" title="19.9. Secure TCP/IP Connections with SSL">Section 19.9</a> for more information).
Otherwise, the <code class="literal">hostssl</code> record is ignored except for
logging a warning that it cannot match any connections.
</p></dd><dt><span class="term"><code class="literal">hostnossl</code></span></dt><dd><p>
This record type has the opposite behavior of <code class="literal">hostssl</code>;
it only matches connection attempts made over
TCP/IP that do not use <acronym class="acronym">SSL</acronym>.
</p></dd><dt><span class="term"><code class="literal">hostgssenc</code></span></dt><dd><p>
This record matches connection attempts made using TCP/IP,
but only when the connection is made with <acronym class="acronym">GSSAPI</acronym>
encryption.
</p><p>
To make use of this option the server must be built with
<acronym class="acronym">GSSAPI</acronym> support. Otherwise,
the <code class="literal">hostgssenc</code> record is ignored except for logging
a warning that it cannot match any connections.
</p></dd><dt><span class="term"><code class="literal">hostnogssenc</code></span></dt><dd><p>
This record type has the opposite behavior of <code class="literal">hostgssenc</code>;
it only matches connection attempts made over
TCP/IP that do not use <acronym class="acronym">GSSAPI</acronym> encryption.
</p></dd><dt><span class="term"><em class="replaceable"><code>database</code></em></span></dt><dd><p>
Specifies which database name(s) this record matches. The value
<code class="literal">all</code> specifies that it matches all databases.
The value <code class="literal">sameuser</code> specifies that the record
matches if the requested database has the same name as the
requested user. The value <code class="literal">samerole</code> specifies that
the requested user must be a member of the role with the same
name as the requested database. (<code class="literal">samegroup</code> is an
obsolete but still accepted spelling of <code class="literal">samerole</code>.)
Superusers are not considered to be members of a role for the
purposes of <code class="literal">samerole</code> unless they are explicitly
members of the role, directly or indirectly, and not just by
virtue of being a superuser.
The value <code class="literal">replication</code> specifies that the record
matches if a physical replication connection is requested, however, it
doesn't match with logical replication connections. Note that physical
replication connections do not specify any particular database whereas
logical replication connections do specify it.
Otherwise, this is the name of
a specific <span class="productname">PostgreSQL</span> database.
Multiple database names can be supplied by separating them with
commas. A separate file containing database names can be specified by
preceding the file name with <code class="literal">@</code>.
</p></dd><dt><span class="term"><em class="replaceable"><code>user</code></em></span></dt><dd><p>
Specifies which database user name(s) this record
matches. The value <code class="literal">all</code> specifies that it
matches all users. Otherwise, this is either the name of a specific
database user, or a group name preceded by <code class="literal">+</code>.
(Recall that there is no real distinction between users and groups
in <span class="productname">PostgreSQL</span>; a <code class="literal">+</code> mark really means
<span class="quote">“<span class="quote">match any of the roles that are directly or indirectly members
of this role</span>”</span>, while a name without a <code class="literal">+</code> mark matches
only that specific role.) For this purpose, a superuser is only
considered to be a member of a role if they are explicitly a member
of the role, directly or indirectly, and not just by virtue of
being a superuser.
Multiple user names can be supplied by separating them with commas.
A separate file containing user names can be specified by preceding the
file name with <code class="literal">@</code>.
</p></dd><dt><span class="term"><em class="replaceable"><code>address</code></em></span></dt><dd><p>
Specifies the client machine address(es) that this record
matches. This field can contain either a host name, an IP
address range, or one of the special key words mentioned below.
</p><p>
An IP address range is specified using standard numeric notation
for the range's starting address, then a slash (<code class="literal">/</code>)
and a <acronym class="acronym">CIDR</acronym> mask length. The mask
length indicates the number of high-order bits of the client
IP address that must match. Bits to the right of this should
be zero in the given IP address.
There must not be any white space between the IP address, the
<code class="literal">/</code>, and the CIDR mask length.
</p><p>
Typical examples of an IPv4 address range specified this way are
<code class="literal">172.20.143.89/32</code> for a single host, or
<code class="literal">172.20.143.0/24</code> for a small network, or
<code class="literal">10.6.0.0/16</code> for a larger one.
An IPv6 address range might look like <code class="literal">::1/128</code>
for a single host (in this case the IPv6 loopback address) or
<code class="literal">fe80::7a31:c1ff:0000:0000/96</code> for a small
network.
<code class="literal">0.0.0.0/0</code> represents all
IPv4 addresses, and <code class="literal">::0/0</code> represents
all IPv6 addresses.
To specify a single host, use a mask length of 32 for IPv4 or
128 for IPv6. In a network address, do not omit trailing zeroes.
</p><p>
An entry given in IPv4 format will match only IPv4 connections,
and an entry given in IPv6 format will match only IPv6 connections,
even if the represented address is in the IPv4-in-IPv6 range.
Note that entries in IPv6 format will be rejected if the system's
C library does not have support for IPv6 addresses.
</p><p>
You can also write <code class="literal">all</code> to match any IP address,
<code class="literal">samehost</code> to match any of the server's own IP
addresses, or <code class="literal">samenet</code> to match any address in any
subnet that the server is directly connected to.
</p><p>
If a host name is specified (anything that is not an IP address
range or a special key word is treated as a host name),
that name is compared with the result of a reverse name
resolution of the client's IP address (e.g., reverse DNS
lookup, if DNS is used). Host name comparisons are case
insensitive. If there is a match, then a forward name
resolution (e.g., forward DNS lookup) is performed on the host
name to check whether any of the addresses it resolves to are
equal to the client's IP address. If both directions match,
then the entry is considered to match. (The host name that is
used in <code class="filename">pg_hba.conf</code> should be the one that
address-to-name resolution of the client's IP address returns,
otherwise the line won't be matched. Some host name databases
allow associating an IP address with multiple host names, but
the operating system will only return one host name when asked
to resolve an IP address.)
</p><p>
A host name specification that starts with a dot
(<code class="literal">.</code>) matches a suffix of the actual host
name. So <code class="literal">.example.com</code> would match
<code class="literal">foo.example.com</code> (but not just
<code class="literal">example.com</code>).
</p><p>
When host names are specified
in <code class="filename">pg_hba.conf</code>, you should make sure that
name resolution is reasonably fast. It can be of advantage to
set up a local name resolution cache such
as <code class="command">nscd</code>. Also, you may wish to enable the
configuration parameter <code class="varname">log_hostname</code> to see
the client's host name instead of the IP address in the log.
</p><p>
These fields do not apply to <code class="literal">local</code> records.
</p><div class="note"><h3 class="title">Note</h3><p>
Users sometimes wonder why host names are handled
in this seemingly complicated way, with two name resolutions
including a reverse lookup of the client's IP address. This
complicates use of the feature in case the client's reverse DNS
entry is not set up or yields some undesirable host name.
It is done primarily for efficiency: this way, a connection attempt
requires at most two resolver lookups, one reverse and one forward.
If there is a resolver problem with some address, it becomes only
that client's problem. A hypothetical alternative
implementation that only did forward lookups would have to
resolve every host name mentioned in
<code class="filename">pg_hba.conf</code> during every connection attempt.
That could be quite slow if many names are listed.
And if there is a resolver problem with one of the host names,
it becomes everyone's problem.
</p><p>
Also, a reverse lookup is necessary to implement the suffix
matching feature, because the actual client host name needs to
be known in order to match it against the pattern.
</p><p>
Note that this behavior is consistent with other popular
implementations of host name-based access control, such as the
Apache HTTP Server and TCP Wrappers.
</p></div></dd><dt><span class="term"><em class="replaceable"><code>IP-address</code></em><br /></span><span class="term"><em class="replaceable"><code>IP-mask</code></em></span></dt><dd><p>
These two fields can be used as an alternative to the
<em class="replaceable"><code>IP-address</code></em><code class="literal">/</code><em class="replaceable"><code>mask-length</code></em>
notation. Instead of
specifying the mask length, the actual mask is specified in a
separate column. For example, <code class="literal">255.0.0.0</code> represents an IPv4
CIDR mask length of 8, and <code class="literal">255.255.255.255</code> represents a
CIDR mask length of 32.
</p><p>
These fields do not apply to <code class="literal">local</code> records.
</p></dd><dt><span class="term"><em class="replaceable"><code>auth-method</code></em></span></dt><dd><p>
Specifies the authentication method to use when a connection matches
this record. The possible choices are summarized here; details
are in <a class="xref" href="auth-methods.html" title="21.3. Authentication Methods">Section 21.3</a>. All the options
are lower case and treated case sensitively, so even acronyms like
<code class="literal">ldap</code> must be specified as lower case.
</p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">trust</code></span></dt><dd><p>
Allow the connection unconditionally. This method
allows anyone that can connect to the
<span class="productname">PostgreSQL</span> database server to login as
any <span class="productname">PostgreSQL</span> user they wish,
without the need for a password or any other authentication. See <a class="xref" href="auth-trust.html" title="21.4. Trust Authentication">Section 21.4</a> for details.
</p></dd><dt><span class="term"><code class="literal">reject</code></span></dt><dd><p>
Reject the connection unconditionally. This is useful for
<span class="quote">“<span class="quote">filtering out</span>”</span> certain hosts from a group, for example a
<code class="literal">reject</code> line could block a specific host from connecting,
while a later line allows the remaining hosts in a specific
network to connect.
</p></dd><dt><span class="term"><code class="literal">scram-sha-256</code></span></dt><dd><p>
Perform SCRAM-SHA-256 authentication to verify the user's
password. See <a class="xref" href="auth-password.html" title="21.5. Password Authentication">Section 21.5</a> for details.
</p></dd><dt><span class="term"><code class="literal">md5</code></span></dt><dd><p>
Perform SCRAM-SHA-256 or MD5 authentication to verify the
user's password. See <a class="xref" href="auth-password.html" title="21.5. Password Authentication">Section 21.5</a>
for details.
</p></dd><dt><span class="term"><code class="literal">password</code></span></dt><dd><p>
Require the client to supply an unencrypted password for
authentication.
Since the password is sent in clear text over the
network, this should not be used on untrusted networks.
See <a class="xref" href="auth-password.html" title="21.5. Password Authentication">Section 21.5</a> for details.
</p></dd><dt><span class="term"><code class="literal">gss</code></span></dt><dd><p>
Use GSSAPI to authenticate the user. This is only
available for TCP/IP connections. See <a class="xref" href="gssapi-auth.html" title="21.6. GSSAPI Authentication">Section 21.6</a> for details. It can be used in conjunction
with GSSAPI encryption.
</p></dd><dt><span class="term"><code class="literal">sspi</code></span></dt><dd><p>
Use SSPI to authenticate the user. This is only
available on Windows. See <a class="xref" href="sspi-auth.html" title="21.7. SSPI Authentication">Section 21.7</a> for details.
</p></dd><dt><span class="term"><code class="literal">ident</code></span></dt><dd><p>
Obtain the operating system user name of the client
by contacting the ident server on the client
and check if it matches the requested database user name.
Ident authentication can only be used on TCP/IP
connections. When specified for local connections, peer
authentication will be used instead.
See <a class="xref" href="auth-ident.html" title="21.8. Ident Authentication">Section 21.8</a> for details.
</p></dd><dt><span class="term"><code class="literal">peer</code></span></dt><dd><p>
Obtain the client's operating system user name from the operating
system and check if it matches the requested database user name.
This is only available for local connections.
See <a class="xref" href="auth-peer.html" title="21.9. Peer Authentication">Section 21.9</a> for details.
</p></dd><dt><span class="term"><code class="literal">ldap</code></span></dt><dd><p>
Authenticate using an <acronym class="acronym">LDAP</acronym> server. See <a class="xref" href="auth-ldap.html" title="21.10. LDAP Authentication">Section 21.10</a> for details.
</p></dd><dt><span class="term"><code class="literal">radius</code></span></dt><dd><p>
Authenticate using a RADIUS server. See <a class="xref" href="auth-radius.html" title="21.11. RADIUS Authentication">Section 21.11</a> for details.
</p></dd><dt><span class="term"><code class="literal">cert</code></span></dt><dd><p>
Authenticate using SSL client certificates. See
<a class="xref" href="auth-cert.html" title="21.12. Certificate Authentication">Section 21.12</a> for details.
</p></dd><dt><span class="term"><code class="literal">pam</code></span></dt><dd><p>
Authenticate using the Pluggable Authentication Modules
(PAM) service provided by the operating system. See <a class="xref" href="auth-pam.html" title="21.13. PAM Authentication">Section 21.13</a> for details.
</p></dd><dt><span class="term"><code class="literal">bsd</code></span></dt><dd><p>
Authenticate using the BSD Authentication service provided by the
operating system. See <a class="xref" href="auth-bsd.html" title="21.14. BSD Authentication">Section 21.14</a> for details.
</p></dd></dl></div><p>
</p></dd><dt><span class="term"><em class="replaceable"><code>auth-options</code></em></span></dt><dd><p>
After the <em class="replaceable"><code>auth-method</code></em> field, there can be field(s) of
the form <em class="replaceable"><code>name</code></em><code class="literal">=</code><em class="replaceable"><code>value</code></em> that
specify options for the authentication method. Details about which
options are available for which authentication methods appear below.
</p><p>
In addition to the method-specific options listed below, there is a
method-independent authentication option <code class="literal">clientcert</code>, which
can be specified in any <code class="literal">hostssl</code> record.
This option can be set to <code class="literal">verify-ca</code> or
<code class="literal">verify-full</code>. Both options require the client
to present a valid (trusted) SSL certificate, while
<code class="literal">verify-full</code> additionally enforces that the
<code class="literal">cn</code> (Common Name) in the certificate matches
the username or an applicable mapping.
This behavior is similar to the <code class="literal">cert</code> authentication
method (see <a class="xref" href="auth-cert.html" title="21.12. Certificate Authentication">Section 21.12</a>) but enables pairing
the verification of client certificates with any authentication
method that supports <code class="literal">hostssl</code> entries.
</p><p>
On any record using client certificate authentication (i.e. one
using the <code class="literal">cert</code> authentication method or one
using the <code class="literal">clientcert</code> option), you can specify
which part of the client certificate credentials to match using
the <code class="literal">clientname</code> option. This option can have one
of two values. If you specify <code class="literal">clientname=CN</code>, which
is the default, the username is matched against the certificate's
<code class="literal">Common Name (CN)</code>. If instead you specify
<code class="literal">clientname=DN</code> the username is matched against the
entire <code class="literal">Distinguished Name (DN)</code> of the certificate.
This option is probably best used in conjunction with a username map.
The comparison is done with the <code class="literal">DN</code> in
<a class="ulink" href="https://tools.ietf.org/html/rfc2253" target="_top">RFC 2253</a>
format. To see the <code class="literal">DN</code> of a client certificate
in this format, do
</p><pre class="programlisting">
openssl x509 -in myclient.crt -noout --subject -nameopt RFC2253 | sed "s/^subject=//"
</pre><p>
Care needs to be taken when using this option, especially when using
regular expression matching against the <code class="literal">DN</code>.
</p></dd></dl></div><p>
</p><p>
Files included by <code class="literal">@</code> constructs are read as lists of names,
which can be separated by either whitespace or commas. Comments are
introduced by <code class="literal">#</code>, just as in
<code class="filename">pg_hba.conf</code>, and nested <code class="literal">@</code> constructs are
allowed. Unless the file name following <code class="literal">@</code> is an absolute
path, it is taken to be relative to the directory containing the
referencing file.
</p><p>
Since the <code class="filename">pg_hba.conf</code> records are examined
sequentially for each connection attempt, the order of the records is
significant. Typically, earlier records will have tight connection
match parameters and weaker authentication methods, while later
records will have looser match parameters and stronger authentication
methods. For example, one might wish to use <code class="literal">trust</code>
authentication for local TCP/IP connections but require a password for
remote TCP/IP connections. In this case a record specifying
<code class="literal">trust</code> authentication for connections from 127.0.0.1 would
appear before a record specifying password authentication for a wider
range of allowed client IP addresses.
</p><p>
The <code class="filename">pg_hba.conf</code> file is read on start-up and when
the main server process receives a
<span class="systemitem">SIGHUP</span><a id="id-1.6.8.8.9.3" class="indexterm"></a>
signal. If you edit the file on an
active system, you will need to signal the postmaster
(using <code class="literal">pg_ctl reload</code>, calling the SQL function
<code class="function">pg_reload_conf()</code>, or using <code class="literal">kill
-HUP</code>) to make it re-read the file.
</p><div class="note"><h3 class="title">Note</h3><p>
The preceding statement is not true on Microsoft Windows: there, any
changes in the <code class="filename">pg_hba.conf</code> file are immediately
applied by subsequent new connections.
</p></div><p>
The system view
<a class="link" href="view-pg-hba-file-rules.html" title="54.9. pg_hba_file_rules"><code class="structname">pg_hba_file_rules</code></a>
can be helpful for pre-testing changes to the <code class="filename">pg_hba.conf</code>
file, or for diagnosing problems if loading of the file did not have the
desired effects. Rows in the view with
non-null <code class="structfield">error</code> fields indicate problems in the
corresponding lines of the file.
</p><div class="tip"><h3 class="title">Tip</h3><p>
To connect to a particular database, a user must not only pass the
<code class="filename">pg_hba.conf</code> checks, but must have the
<code class="literal">CONNECT</code> privilege for the database. If you wish to
restrict which users can connect to which databases, it's usually
easier to control this by granting/revoking <code class="literal">CONNECT</code> privilege
than to put the rules in <code class="filename">pg_hba.conf</code> entries.
</p></div><p>
Some examples of <code class="filename">pg_hba.conf</code> entries are shown in
<a class="xref" href="auth-pg-hba-conf.html#EXAMPLE-PG-HBA.CONF" title="Example 21.1. Example pg_hba.conf Entries">Example 21.1</a>. See the next section for details on the
different authentication methods.
</p><div class="example" id="EXAMPLE-PG-HBA.CONF"><p class="title"><strong>Example 21.1. Example <code class="filename">pg_hba.conf</code> Entries</strong></p><div class="example-contents"><pre class="programlisting">
# Allow any user on the local system to connect to any database with
# any database user name using Unix-domain sockets (the default for local
# connections).
#
# TYPE DATABASE USER ADDRESS METHOD
local all all trust
# The same using local loopback TCP/IP connections.
#
# TYPE DATABASE USER ADDRESS METHOD
host all all 127.0.0.1/32 trust
# The same as the previous line, but using a separate netmask column
#
# TYPE DATABASE USER IP-ADDRESS IP-MASK METHOD
host all all 127.0.0.1 255.255.255.255 trust
# The same over IPv6.
#
# TYPE DATABASE USER ADDRESS METHOD
host all all ::1/128 trust
# The same using a host name (would typically cover both IPv4 and IPv6).
#
# TYPE DATABASE USER ADDRESS METHOD
host all all localhost trust
# Allow any user from any host with IP address 192.168.93.x to connect
# to database "postgres" as the same user name that ident reports for
# the connection (typically the operating system user name).
#
# TYPE DATABASE USER ADDRESS METHOD
host postgres all 192.168.93.0/24 ident
# Allow any user from host 192.168.12.10 to connect to database
# "postgres" if the user's password is correctly supplied.
#
# TYPE DATABASE USER ADDRESS METHOD
host postgres all 192.168.12.10/32 scram-sha-256
# Allow any user from hosts in the example.com domain to connect to
# any database if the user's password is correctly supplied.
#
# Require SCRAM authentication for most users, but make an exception
# for user 'mike', who uses an older client that doesn't support SCRAM
# authentication.
#
# TYPE DATABASE USER ADDRESS METHOD
host all mike .example.com md5
host all all .example.com scram-sha-256
# In the absence of preceding "host" lines, these three lines will
# reject all connections from 192.168.54.1 (since that entry will be
# matched first), but allow GSSAPI-encrypted connections from anywhere else
# on the Internet. The zero mask causes no bits of the host IP address to
# be considered, so it matches any host. Unencrypted GSSAPI connections
# (which "fall through" to the third line since "hostgssenc" only matches
# encrypted GSSAPI connections) are allowed, but only from 192.168.12.10.
#
# TYPE DATABASE USER ADDRESS METHOD
host all all 192.168.54.1/32 reject
hostgssenc all all 0.0.0.0/0 gss
host all all 192.168.12.10/32 gss
# Allow users from 192.168.x.x hosts to connect to any database, if
# they pass the ident check. If, for example, ident says the user is
# "bryanh" and he requests to connect as PostgreSQL user "guest1", the
# connection is allowed if there is an entry in pg_ident.conf for map
# "omicron" that says "bryanh" is allowed to connect as "guest1".
#
# TYPE DATABASE USER ADDRESS METHOD
host all all 192.168.0.0/16 ident map=omicron
# If these are the only three lines for local connections, they will
# allow local users to connect only to their own databases (databases
# with the same name as their database user name) except for administrators
# and members of role "support", who can connect to all databases. The file
# $PGDATA/admins contains a list of names of administrators. Passwords
# are required in all cases.
#
# TYPE DATABASE USER ADDRESS METHOD
local sameuser all md5
local all @admins md5
local all +support md5
# The last two lines above can be combined into a single line:
local all @admins,+support md5
# The database column can also use lists and file names:
local db1,db2,@demodbs all md5
</pre></div></div><br class="example-break" /></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="client-authentication.html" title="Chapter 21. Client Authentication">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="client-authentication.html" title="Chapter 21. Client Authentication">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="auth-username-maps.html" title="21.2. User Name Maps">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 21. Client Authentication </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 15.5 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 21.2. User Name Maps</td></tr></table></div></body></html>
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