Blame | Last modification | View Log | RSS feed
# VIRTUAL(5) VIRTUAL(5)## NAME# virtual - Postfix virtual alias table format## SYNOPSIS# postmap /etc/postfix/virtual## postmap -q "string" /etc/postfix/virtual## postmap -q - /etc/postfix/virtual <inputfile## DESCRIPTION# The optional virtual(5) alias table rewrites recipient# addresses for all local, all virtual, and all remote mail# destinations. This is unlike the aliases(5) table which# is used only for local(8) delivery. Virtual aliasing is# recursive, and is implemented by the Postfix cleanup(8)# daemon before mail is queued.## 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. Use# canonical(5) mapping to rewrite header and envelope# addresses in general.## Normally, the virtual(5) 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" 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 expres-# sions, or lookups can be directed to TCP-based server. In# those case, the lookups are done in a slightly different# way as described below under "REGULAR EXPRESSION TABLES"# or "TCP-BASED TABLES".## CASE FOLDING# 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.## TABLE FORMAT# The input format for the postmap(1) command is as follows:## 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.## TABLE SEARCH ORDER# 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, ...# Redirect mail for user@domain to address. This# form has the highest precedence.## user address, address, ...# Redirect mail for user@site to address when site is# equal to $myorigin, when site is listed in $mydes-# tination, or when it is listed in $inet_interfaces# or $proxy_interfaces.## This functionality overlaps with functionality of# the local aliases(5) database. The difference is# that virtual(5) mapping can be applied to non-local# addresses.## @domain address, address, ...# Redirect mail for other users in domain to address.# This form has the lowest precedence.## Note: @domain is a wild-card. With this form, the# Postfix SMTP server accepts mail for any recipient# in domain, regardless of whether that recipient# exists. This may turn your mail system into a# backscatter source: Postfix first accepts mail for# non-existent recipients and then tries to return# that mail as "undeliverable" to the often forged# sender address.## RESULT ADDRESS REWRITING# The lookup result is subject to address rewriting:## o When the result has the form @otherdomain, the# result becomes the same user in otherdomain. This# works only for the first address in a multi-address# lookup result.## o When "append_at_myorigin=yes", append "@$myorigin"# to addresses without "@domain".## o When "append_dot_mydomain=yes", append ".$mydomain"# to addresses without ".domain".## 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.## The propagate_unmatched_extensions parameter controls# whether 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 ta-# ble, 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.## TCP-BASED TABLES# This section describes how the table lookups change when# lookups are directed to a TCP-based server. For a descrip-# tion of the TCP client/server lookup protocol, see tcp_ta-# ble(5). This feature is not available up to and including# Postfix version 2.4.## Each lookup operation uses the entire address once. 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.## Results are the same as with indexed file lookups.## 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.## propagate_unmatched_extensions# A list of address rewriting or forwarding mecha-# nisms that propagate an address extension from the# original address to the result. Specify zero or# more of canonical, virtual, alias, forward,# include, or generic.## 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.## proxy_interfaces# Other interfaces that this machine receives mail on# by way of a proxy agent or network address transla-# tor.## SEE ALSO# cleanup(8), canonicalize and enqueue mail# postmap(1), Postfix lookup table manager# postconf(5), configuration parameters# canonical(5), canonical address mapping## README FILES# Use "postconf readme_directory" or "postconf html_direc-# tory" to locate this information.# ADDRESS_REWRITING_README, address rewriting guide# DATABASE_README, Postfix lookup table overview# VIRTUAL_README, domain hosting guide## 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)