virtual - format of Postfix virtual table
The optional virtual table specifies address redirections for local and non-local recipi-
ents or domains. The redirections are used by the cleanup(8) daemon. The redirections are
The virtual redirection is applied only to recipient envelope addresses, and does not
affect message headers. Think Sendmail rule set S0, if you like. Use canonical(5) mapping
to rewrite header and envelope addresses in general.
Normally, the virtual 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 expressions. In that case, the lookups are done in a slightly different
way as described below.
POSTFIX-STYLE VIRTUAL DOMAINS
With a Postfix-style virtual domain, the virtual domain has its own user name space. Local
(i.e. non-virtual) usernames are not visible in a Postfix-style virtual domain. In partic-
ular, local aliases(5) and mailing lists are not visible as firstname.lastname@example.org.
Use a Sendmail-style virtual domain (see below) if local usernames, aliases(5) or mailing
lists should be visible as email@example.com.
Support for a Postfix-style virtual domain looks like:
virtual.domain anything (right-hand content does not matter)
firstname.lastname@example.org address2, address3
The virtual.domain anything entry is required for a Postfix-style virtual domain.
Do not list a Postfix-style virtual domain in the main.cf mydestination configuration
parameter. Such an entry is required only for a Sendmail-style virtual domain.
With a Postfix-style virtual domain, the Postfix SMTP server accepts mail for known-
email@example.com and rejects mail for firstname.lastname@example.org as undeliverable.
SENDMAIL-STYLE VIRTUAL DOMAINS
With a Sendmail-style virtual domain, every local (i.e. non-virtual) username is visible
in the virtual domain. In particular, every local alias and mailing list is visible as
Use a Postfix-style virtual domain (see above) if local usernames, aliases(5) or mailing
lists should not be visible as email@example.com.
Support for a Sendmail-style virtual domain looks like:
mydestination = $myhostname localhost.$mydomain $mydomain
firstname.lastname@example.org address2, address3
The main.cf mydestination entry is required for a Sendmail-style virtual domain.
Do not specify a virtual.domain anything virtual map entry for a Sendmail-style virtual
domain. Such an entry is required only with a Postfix-style virtual domain.
With a Sendmail-style virtual domain, the Postfix local delivery agent delivers mail for
an unknown email@example.com to a local (i.e. non-virtual) user that has the same name;
if no such recipient exists, the Postfix local delivery agent bounces the mail to the
The format of the virtual table is as follows, mappings being tried in the order as listed
in this manual page:
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 `#'.
A logical line starts with non-whitespace text. A line that starts with whitespace
continues a logical 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 prece-
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 alias(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
In all the above forms, when address has the form @otherdomain, the result is the same
user in otherdomain. This works for the first address in the expansion only.
When a mail address localpart contains the optional recipient 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 propagated to the result of table
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 reg-
exp_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 con-
stituent 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 paren-
thesized substrings from the pattern can be interpolated as $1, $2 and so on.
The table format does not understand quoting conventions.
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.
List of virtual mapping tables.
Other parameters of interest:
The network interface addresses that this system receives mail on.
List of domains that this mail system considers local.
The domain that is appended to locally-posted mail.
Give special treatment to owner-xxx and xxx-request addresses.
cleanup(8) canonicalize and enqueue mail
postmap(1) create mapping table
pcre_table(5) format of PCRE tables
regexp_table(5) format of POSIX regular expression tables
The Secure Mailer license must be distributed with this software.
IBM T.J. Watson Research
P.O. Box 704
Yorktown Heights, NY 10598, USA