VIRTUAL(5) | VIRTUAL(5) |
postmap -q "string" /etc/postfix/virtual
postmap -q - /etc/postfix/virtual <inputfile
The main applications of virtual aliasing are:
• | To redirect mail for one address to one or more addresses. |
• |
To implement virtual alias domains where all addresses are aliased to addresses in other domains. |
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 expressions, 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".
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 logical line. |
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 $ mydestination, or when it is listed in $inet_interfaces or $ proxy_interfaces. |
@domain address, address, ... |
Redirect mail for other users in domain to address. This form has the lowest precedence. |
• | 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. |
• | When "append_at_myorigin=yes", append "@$myorigin" to addresses without "@domain". |
• | When "append_dot_mydomain=yes", append " .$mydomain" to addresses without ".domain". |
The propagate_unmatched_extensions parameter controls whether an unmatched address extension ( +foo) is propagated to the result of table lookup.
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.
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
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.
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.
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.
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 mechanisms 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 Postfix 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 translator. |
August 25, 2011 |