# VIRTUAL(5) VIRTUAL(5) # # NAME # virtual - format of Postfix virtual alias table # # SYNOPSIS # postmap /etc/postfix/virtual # # postmap -q "string" /etc/postfix/virtual # # postmap -q - /etc/postfix/virtual <inputfile # # DESCRIPTION # The optional virtual alias table specifies address alias- # ing for arbitrary local or non-local recipient addresses. # Virtual aliasing is recursive, and is done by the Postfix # cleanup(8) daemon. # # The main applications of virtual aliasing are: # # o To redirect mail for one address to one or more # addresses. # # o To implement virtual alias domains where all # addresses are aliased to addresses in other # domains. # # Virtual alias domains are not to be confused with # the virtual mailbox domains that are implemented # with the Postfix virtual(8) mail delivery agent. # With virtual mailbox domains, each recipient # address can have its own mailbox. # # Virtual aliasing is applied only to recipient envelope # addresses, and does not affect message headers. Think # Sendmail rule set S0, if you like. Use canonical(5) map- # ping to rewrite header and envelope addresses in general. # # Normally, the virtual alias table is specified as a text # file that serves as input to the postmap(1) command. The # result, an indexed file in dbm or db format, is used for # fast searching by the mail system. Execute the command # postmap /etc/postfix/virtual in order to rebuild the # indexed file after changing the 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 expres- # sions. In that case, the lookups are done in a slightly # different way as described below. # # TABLE FORMAT # The format of the virtual table is as follows, mappings # being tried in the order as listed in this manual page: # # pattern result # When pattern matches a mail address, replace it by # the corresponding result. # # blank lines and comments # Empty lines and whitespace-only lines are ignored, # as are lines whose first non-whitespace character # is a `#'. # # multi-line text # A logical line starts with non-whitespace text. A # line that starts with whitespace continues a logi- # cal line. # # 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: # # user@domain address, address, ... # Mail for user@domain is redirected to address. # This form has the highest precedence. # # user address, address, ... # Mail for user@site is redirected to address when # site is equal to $myorigin, when site is listed in # $mydestination, or when it is listed in # $inet_interfaces. # # This functionality overlaps with functionality of # the local aliases(5) database. The difference is # that virtual mapping can be applied to non-local # addresses. # # @domain address, address, ... # Mail for any user in domain is redirected to # address. This form has the lowest precedence. # # In all the above forms, when address has the form @other- # domain, the result is the same user in otherdomain. This # works for the first address in the expansion only. # # ADDRESS EXTENSION # When a mail address localpart contains the optional recip- # ient delimiter (e.g., user+foo@domain), the lookup order # becomes: user+foo@domain, user@domain, user+foo, user, and # @domain. An unmatched address extension (+foo) is propa- # gated to the result of table lookup. # # VIRTUAL ALIAS DOMAINS # Besides virtual aliases, the virtual alias table can also # be used to implement virtual alias domains. With a virtual # alias domain, all recipient addresses are aliased to # addresses in other domains. # # Virtual alias domains are not to be confused with the vir- # tual mailbox domains that are implemented with the Postfix # virtual(8) mail delivery agent. With virtual mailbox # domains, each recipient address can have its own mailbox. # # With a virtual alias domain, the virtual domain has its # own user name space. Local (i.e. non-virtual) usernames # are not visible in a virtual alias domain. In particular, # local aliases(5) and local mailing lists are not visible # as localname@virtual-alias.domain. # # Support for a virtual alias domain looks like: # # /etc/postfix/main.cf: # virtual_alias_maps = hash:/etc/postfix/virtual # # Note: some systems use dbm databases instead of hash. # See the output from postconf -m for available database # types. # # /etc/postfix/virtual: # virtual-alias.domain anything (right-hand content does not matter) # postmaster@virtual-alias.domain postmaster # user1@virtual-alias.domain address1 # user2@virtual-alias.domain address2, address3 # # The virtual-alias.domain anything entry is required for a # virtual alias domain. Without this entry, mail is rejected # with "relay access denied", or bounces with "mail loops # back to myself". # # Do not specify virtual alias domain names in the main.cf # mydestination or relay_domains configuration parameters. # # With a virtual alias domain, the Postfix SMTP server # accepts mail for known-user@virtual-alias.domain, and # rejects mail for unknown-user@virtual-alias.domain as # undeliverable. # # Instead of specifying the virtual alias domain name via # the virtual_alias_maps table, you may also specify it via # the main.cf virtual_alias_domains configuration parameter. # This latter parameter uses the same syntax as the main.cf # mydestination configuration parameter. # # REGULAR EXPRESSION TABLES # 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 regexp_table(5) or pcre_table(5). # # Each pattern is a regular expression that is applied to # the entire address being looked up. Thus, user@domain mail # addresses are not broken up into their user and @domain # constituent parts, nor is user+foo broken up into user and # foo. # # Patterns are applied in the order as specified in the # table, until a pattern is found that matches the search # string. # # Results are the same as with indexed file lookups, with # the additional feature that parenthesized substrings from # the pattern can be interpolated as $1, $2 and so on. # # BUGS # The table format does not understand quoting conventions. # # CONFIGURATION PARAMETERS # The following main.cf parameters are especially relevant # to this topic. See the Postfix main.cf file for syntax # details and for default values. Use the postfix reload # command after a configuration change. # # virtual_alias_maps # List of virtual aliasing tables. # # virtual_alias_domains # List of virtual alias domains. This uses the same # syntax as the mydestination parameter. # # Other parameters of interest: # # inet_interfaces # The network interface addresses that this system # receives mail on. You need to stop and start Post- # fix when this parameter changes. # # mydestination # List of domains that this mail system considers # local. # # myorigin # The domain that is appended to any address that # does not have a domain. # # owner_request_special # Give special treatment to owner-xxx and xxx-request # addresses. # # SEE ALSO # cleanup(8) canonicalize and enqueue mail # postmap(1) create mapping table # regexp_table(5) POSIX regular expression table format # pcre_table(5) Perl Compatible Regular Expression table format # # LICENSE # The Secure Mailer license must be distributed with this # software. # # AUTHOR(S) # Wietse Venema # IBM T.J. Watson Research # P.O. Box 704 # Yorktown Heights, NY 10598, USA # # VIRTUAL(5)