diff options
Diffstat (limited to '')
| -rw-r--r-- | man/man5/access.5 | 490 |
1 files changed, 490 insertions, 0 deletions
diff --git a/man/man5/access.5 b/man/man5/access.5 new file mode 100644 index 0000000..4fb7b6b --- /dev/null +++ b/man/man5/access.5 @@ -0,0 +1,490 @@ +.TH ACCESS 5 +.ad +.fi +.SH NAME +access +\- +Postfix SMTP server access table +.SH "SYNOPSIS" +.na +.nf +\fBpostmap /etc/postfix/access\fR + +\fBpostmap \-q "\fIstring\fB" /etc/postfix/access\fR + +\fBpostmap \-q \- /etc/postfix/access <\fIinputfile\fR +.SH DESCRIPTION +.ad +.fi +This document describes access control on remote SMTP client +information: host names, network addresses, and envelope +sender or recipient addresses; it is implemented by the +Postfix SMTP server. See \fBheader_checks\fR(5) or +\fBbody_checks\fR(5) for access control on the content of +email messages. + +Normally, the \fBaccess\fR(5) table is specified as a text file +that serves as input to the \fBpostmap\fR(1) command. +The result, an indexed file in \fBdbm\fR or \fBdb\fR format, +is used for fast searching by the mail system. Execute the +command "\fBpostmap /etc/postfix/access\fR" to rebuild an +indexed file after changing the corresponding text file. + +When the table is provided via other means such as NIS, LDAP +or SQL, the same lookups are done as for ordinary indexed files. + +Alternatively, the table can be provided as a regular\-expression +map where patterns are given as regular expressions, or lookups +can be directed to TCP\-based server. In those cases, the lookups +are done in a slightly different way as described below under +"REGULAR EXPRESSION TABLES" or "TCP\-BASED TABLES". +.SH "CASE FOLDING" +.na +.nf +.ad +.fi +The search string is folded to lowercase before database +lookup. As of Postfix 2.3, the search string is not case +folded with database types such as regexp: or pcre: whose +lookup fields can match both upper and lower case. +.SH "TABLE FORMAT" +.na +.nf +.ad +.fi +The input format for the \fBpostmap\fR(1) command is as follows: +.IP "\fIpattern action\fR" +When \fIpattern\fR matches a mail address, domain or host address, +perform the corresponding \fIaction\fR. +.IP "blank lines and comments" +Empty lines and whitespace\-only lines are ignored, as +are lines whose first non\-whitespace character is a `#'. +.IP "multi\-line text" +A logical line starts with non\-whitespace text. A line that +starts with whitespace continues a logical line. +.SH "EMAIL ADDRESS PATTERNS" +.na +.nf +.ad +.fi +With lookups from indexed files such as DB or DBM, or from networked +tables such as NIS, LDAP or SQL, patterns are tried in the order as +listed below: +.IP \fIuser\fR@\fIdomain\fR +Matches the specified mail address. +.IP \fIdomain.tld\fR +Matches \fIdomain.tld\fR as the domain part of an email address. +.sp +The pattern \fIdomain.tld\fR also matches subdomains, but only +when the string \fBsmtpd_access_maps\fR is listed in the Postfix +\fBparent_domain_matches_subdomains\fR configuration setting. +.IP \fI.domain.tld\fR +Matches subdomains of \fIdomain.tld\fR, but only when the +string \fBsmtpd_access_maps\fR is not listed in the Postfix +\fBparent_domain_matches_subdomains\fR configuration setting. +.IP \fIuser\fR@ +Matches all mail addresses with the specified user part. +.PP +Note: lookup of the null sender address is not possible with +some types of lookup table. By default, Postfix uses \fB<>\fR +as the lookup key for such addresses. The value is specified with +the \fBsmtpd_null_access_lookup_key\fR parameter in the Postfix +\fBmain.cf\fR file. +.SH "EMAIL ADDRESS EXTENSION" +.na +.nf +.fi +.ad +When a mail address localpart contains the optional recipient delimiter +(e.g., \fIuser+foo\fR@\fIdomain\fR), the lookup order becomes: +\fIuser+foo\fR@\fIdomain\fR, \fIuser\fR@\fIdomain\fR, \fIdomain\fR, +\fIuser+foo\fR@, and \fIuser\fR@. +.SH "HOST NAME/ADDRESS PATTERNS" +.na +.nf +.ad +.fi +With lookups from indexed files such as DB or DBM, or from networked +tables such as NIS, LDAP or SQL, the following lookup patterns are +examined in the order as listed: +.IP \fIdomain.tld\fR +Matches \fIdomain.tld\fR. +.sp +The pattern \fIdomain.tld\fR also matches subdomains, but only +when the string \fBsmtpd_access_maps\fR is listed in the Postfix +\fBparent_domain_matches_subdomains\fR configuration setting. +.IP \fI.domain.tld\fR +Matches subdomains of \fIdomain.tld\fR, but only when the +string \fBsmtpd_access_maps\fR is not listed in the Postfix +\fBparent_domain_matches_subdomains\fR configuration setting. +.IP \fInet.work.addr.ess\fR +.IP \fInet.work.addr\fR +.IP \fInet.work\fR +.IP \fInet\fR +Matches the specified IPv4 host address or subnetwork. An +IPv4 host address is a sequence of four decimal octets +separated by ".". + +Subnetworks are matched by repeatedly truncating the last +".octet" from the remote IPv4 host address string until a +match is found in the access table, or until further +truncation is not possible. + +NOTE 1: The access map lookup key must be in canonical form: +do not specify unnecessary null characters, and do not +enclose network address information with "[]" characters. + +NOTE 2: use the \fBcidr\fR lookup table type to specify +network/netmask patterns. See \fBcidr_table\fR(5) for details. +.IP \fInet:work:addr:ess\fR +.IP \fInet:work:addr\fR +.IP \fInet:work\fR +.IP \fInet\fR +Matches the specified IPv6 host address or subnetwork. An +IPv6 host address is a sequence of three to eight hexadecimal +octet pairs separated by ":". + +Subnetworks are matched by repeatedly truncating the last +":octetpair" from the remote IPv6 host address string until +a match is found in the access table, or until further +truncation is not possible. + +NOTE 1: the truncation and comparison are done with the +string representation of the IPv6 host address. Thus, not +all the ":" subnetworks will be tried. + +NOTE 2: The access map lookup key must be in canonical form: +do not specify unnecessary null characters, and do not +enclose network address information with "[]" characters. + +NOTE 3: use the \fBcidr\fR lookup table type to specify +network/netmask patterns. See \fBcidr_table\fR(5) for details. + +IPv6 support is available in Postfix 2.2 and later. +.SH "ACCEPT ACTIONS" +.na +.nf +.ad +.fi +.IP \fBOK\fR +Accept the address etc. that matches the pattern. +.IP \fIall\-numerical\fR +An all\-numerical result is treated as OK. This format is +generated by address\-based relay authorization schemes +such as pop\-before\-smtp. +.PP +For other accept actions, see "OTHER ACTIONS" below. +.SH "REJECT ACTIONS" +.na +.nf +.ad +.fi +Postfix version 2.3 and later support enhanced status codes +as defined in RFC 3463. +When no code is specified at the beginning of the \fItext\fR +below, Postfix inserts a default enhanced status code of "5.7.1" +in the case of reject actions, and "4.7.1" in the case of +defer actions. See "ENHANCED STATUS CODES" below. +.IP "\fB4\fINN text\fR" +.IP "\fB5\fINN text\fR" +Reject the address etc. that matches the pattern, and respond with +the numerical three\-digit code and text. \fB4\fINN\fR means "try +again later", while \fB5\fINN\fR means "do not try again". + +The following responses have special meaning for the Postfix +SMTP server: +.RS +.IP "\fB421 \fItext\fR (Postfix 2.3 and later)" +.IP "\fB521 \fItext\fR (Postfix 2.6 and later)" +After responding with the numerical three\-digit code and +text, disconnect immediately from the SMTP client. This +frees up SMTP server resources so that they can be made +available to another SMTP client. +.IP +Note: The "521" response should be used only with botnets +and other malware where interoperability is of no concern. +The "send 521 and disconnect" behavior is NOT defined in +the SMTP standard. +.RE +.IP "\fBREJECT \fIoptional text...\fR +Reject the address etc. that matches the pattern. Reply with +"\fB$access_map_reject_code \fIoptional text...\fR" when the +optional text is +specified, otherwise reply with a generic error response message. +.IP "\fBDEFER \fIoptional text...\fR +Reject the address etc. that matches the pattern. Reply with +"\fB$access_map_defer_code \fIoptional text...\fR" when the +optional text is +specified, otherwise reply with a generic error response message. +.sp +This feature is available in Postfix 2.6 and later. +.IP "\fBDEFER_IF_REJECT \fIoptional text...\fR +Defer the request if some later restriction would result in a +REJECT action. Reply with "\fB$access_map_defer_code 4.7.1 +\fIoptional text...\fR" when the +optional text is specified, otherwise reply with a generic error +response message. +.sp +Prior to Postfix 2.6, the SMTP reply code is 450. +.sp +This feature is available in Postfix 2.1 and later. +.IP "\fBDEFER_IF_PERMIT \fIoptional text...\fR +Defer the request if some later restriction would result in a +an explicit or implicit PERMIT action. +Reply with "\fB$access_map_defer_code 4.7.1 \fI optional +text...\fR" when the +optional text is specified, otherwise reply with a generic error +response message. +.sp +Prior to Postfix 2.6, the SMTP reply code is 450. +.sp +This feature is available in Postfix 2.1 and later. +.PP +For other reject actions, see "OTHER ACTIONS" below. +.SH "OTHER ACTIONS" +.na +.nf +.ad +.fi +.IP \fIrestriction...\fR +Apply the named UCE restriction(s) (\fBpermit\fR, \fBreject\fR, +\fBreject_unauth_destination\fR, and so on). +.IP "\fBBCC \fIuser@domain\fR" +Send one copy of the message to the specified recipient. +.sp +If multiple BCC actions are specified within the same SMTP +MAIL transaction, with Postfix 3.0 only the last action +will be used. +.sp +This feature is available in Postfix 3.0 and later. +.IP "\fBDISCARD \fIoptional text...\fR +Claim successful delivery and silently discard the message. +Log the optional text if specified, otherwise log a generic +message. +.sp +Note: this action currently affects all recipients of the message. +To discard only one recipient without discarding the entire message, +use the transport(5) table to direct mail to the discard(8) service. +.sp +This feature is available in Postfix 2.0 and later. +.IP \fBDUNNO\fR +Pretend that the lookup key was not found. This +prevents Postfix from trying substrings of the lookup key +(such as a subdomain name, or a network address subnetwork). +.sp +This feature is available in Postfix 2.0 and later. +.IP "\fBFILTER \fItransport:destination\fR" +After the message is queued, send the entire message through +the specified external content filter. The \fItransport\fR +name specifies the first field of a mail delivery agent +definition in master.cf; the syntax of the next\-hop +\fIdestination\fR is described in the manual page of the +corresponding delivery agent. More information about +external content filters is in the Postfix FILTER_README +file. +.sp +Note 1: do not use $\fInumber\fR regular expression +substitutions for \fItransport\fR or \fIdestination\fR +unless you know that the information has a trusted origin. +.sp +Note 2: this action overrides the main.cf \fBcontent_filter\fR +setting, and affects all recipients of the message. In the +case that multiple \fBFILTER\fR actions fire, only the last +one is executed. +.sp +Note 3: the purpose of the FILTER command is to override +message routing. To override the recipient's \fItransport\fR +but not the next\-hop \fIdestination\fR, specify an empty +filter \fIdestination\fR (Postfix 2.7 and later), or specify +a \fItransport:destination\fR that delivers through a +different Postfix instance (Postfix 2.6 and earlier). Other +options are using the recipient\-dependent \fBtrans\%port\%_maps\fR +or the sen\%der\-dependent +\fBsender\%_de\%pen\%dent\%_de\%fault\%_trans\%port\%_maps\fR +features. +.sp +This feature is available in Postfix 2.0 and later. +.IP "\fBHOLD \fIoptional text...\fR" +Place the message on the \fBhold\fR queue, where it will +sit until someone either deletes it or releases it for +delivery. +Log the optional text if specified, otherwise log a generic +message. + +Mail that is placed on hold can be examined with the +\fBpostcat\fR(1) command, and can be destroyed or released with +the \fBpostsuper\fR(1) command. +.sp +Note: use "\fBpostsuper \-r\fR" to release mail that was kept on +hold for a significant fraction of \fB$maximal_queue_lifetime\fR +or \fB$bounce_queue_lifetime\fR, or longer. Use "\fBpostsuper \-H\fR" +only for mail that will not expire within a few delivery attempts. +.sp +Note: this action currently affects all recipients of the message. +.sp +This feature is available in Postfix 2.0 and later. +.IP "\fBPREPEND \fIheadername: headervalue\fR" +Prepend the specified message header to the message. +When more than one PREPEND action executes, the first +prepended header appears before the second etc. prepended +header. +.sp +Note: this action must execute before the message content +is received; it cannot execute in the context of +\fBsmtpd_end_of_data_restrictions\fR. +.sp +This feature is available in Postfix 2.1 and later. +.IP "\fBREDIRECT \fIuser@domain\fR" +After the message is queued, send the message to the specified +address instead of the intended recipient(s). When multiple +\fBREDIRECT\fR actions fire, only the last one takes effect. +.sp +Note: this action overrides the FILTER action, and currently +overrides all recipients of the message. +.sp +This feature is available in Postfix 2.1 and later. +.IP "\fBINFO \fIoptional text...\fR +Log an informational record with the optional text, together +with client information and if available, with helo, sender, +recipient and protocol information. +.sp +This feature is available in Postfix 3.0 and later. +.IP "\fBWARN \fIoptional text...\fR +Log a warning with the optional text, together with client information +and if available, with helo, sender, recipient and protocol information. +.sp +This feature is available in Postfix 2.1 and later. +.SH "ENHANCED STATUS CODES" +.na +.nf +.ad +.fi +Postfix version 2.3 and later support enhanced status codes +as defined in RFC 3463. +When an enhanced status code is specified in an access +table, it is subject to modification. The following +transformations are needed when the same access table is +used for client, helo, sender, or recipient access restrictions; +they happen regardless of whether Postfix replies to a MAIL +FROM, RCPT TO or other SMTP command. +.IP \(bu +When a sender address matches a REJECT action, the Postfix +SMTP server will transform a recipient DSN status (e.g., +4.1.1\-4.1.6) into the corresponding sender DSN status, and +vice versa. +.IP \(bu +When non\-address information matches a REJECT action (such +as the HELO command argument or the client hostname/address), +the Postfix SMTP server will transform a sender or recipient +DSN status into a generic non\-address DSN status (e.g., +4.0.0). +.SH "REGULAR EXPRESSION TABLES" +.na +.nf +.ad +.fi +This section describes how the table lookups change when the table +is given in the form of regular expressions. For a description of +regular expression lookup table syntax, see \fBregexp_table\fR(5) +or \fBpcre_table\fR(5). + +Each pattern is a regular expression that is applied to the entire +string being looked up. Depending on the application, that string +is an entire client hostname, an entire client IP address, or an +entire mail address. Thus, no parent domain or parent network search +is done, \fIuser@domain\fR mail addresses are not broken up into +their \fIuser@\fR and \fIdomain\fR constituent parts, nor is +\fIuser+foo\fR broken up into \fIuser\fR and \fIfoo\fR. + +Patterns are applied in the order as specified in the table, until a +pattern is found that matches the search string. + +Actions are the same as with indexed file lookups, with +the additional feature that parenthesized substrings from the +pattern can be interpolated as \fB$1\fR, \fB$2\fR and so on. +.SH "TCP-BASED TABLES" +.na +.nf +.ad +.fi +This section describes how the table lookups change when lookups +are directed to a TCP\-based server. For a description of the TCP +client/server lookup protocol, see \fBtcp_table\fR(5). +This feature is not available up to and including Postfix version 2.4. + +Each lookup operation uses the entire query string once. +Depending on the application, that string is an entire client +hostname, an entire client IP address, or an entire mail address. +Thus, no parent domain or parent network search is done, +\fIuser@domain\fR mail addresses are not broken up into +their \fIuser@\fR and \fIdomain\fR constituent parts, nor is +\fIuser+foo\fR broken up into \fIuser\fR and \fIfoo\fR. + +Actions are the same as with indexed file lookups. +.SH "EXAMPLE" +.na +.nf +.ad +.fi +The following example uses an indexed file, so that the +order of table entries does not matter. The example permits +access by the client at address 1.2.3.4 but rejects all +other clients in 1.2.3.0/24. Instead of \fBhash\fR lookup +tables, some systems use \fBdbm\fR. Use the command +"\fBpostconf \-m\fR" to find out what lookup tables Postfix +supports on your system. + +.nf +.na +/etc/postfix/main.cf: + smtpd_client_restrictions = + check_client_access hash:/etc/postfix/access + +/etc/postfix/access: + 1.2.3 REJECT + 1.2.3.4 OK +.fi +.ad + +Execute the command "\fBpostmap /etc/postfix/access\fR" after +editing the file. +.SH BUGS +.ad +.fi +The table format does not understand quoting conventions. +.SH "SEE ALSO" +.na +.nf +postmap(1), Postfix lookup table manager +smtpd(8), SMTP server +postconf(5), configuration parameters +transport(5), transport:nexthop syntax +.SH "README FILES" +.na +.nf +.ad +.fi +Use "\fBpostconf readme_directory\fR" or +"\fBpostconf html_directory\fR" to locate this information. +.na +.nf +SMTPD_ACCESS_README, built\-in SMTP server access control +DATABASE_README, Postfix lookup table overview +.SH "LICENSE" +.na +.nf +.ad +.fi +The Secure Mailer license must be distributed with this software. +.SH "AUTHOR(S)" +.na +.nf +Wietse Venema +IBM T.J. Watson Research +P.O. Box 704 +Yorktown Heights, NY 10598, USA + +Wietse Venema +Google, Inc. +111 8th Avenue +New York, NY 10011, USA |