Some providers host domains that have no (or only a few) local
mailboxes. The main purpose of these domains is to forward mail
elsewhere. The following example shows how to set up example.com
as a mail forwarding domain:
1 /etc/postfix/main.cf:
2
virtual_alias_domains = example.com ...other
hosted domains...
3
virtual_alias_maps = hash:/etc/postfix/virtual
4
5 /etc/postfix/virtual:
6 [email protected] postmaster
7 [email protected] joe@somewhere
8 [email protected] jane@somewhere-else
9 # Uncomment entry below to implement a catch-all address
10 # @example.com jim@yet-another-site
11 ...virtual aliases for more domains...
Notes:
-
Line 2: The
virtual_alias_domains setting tells Postfix
that example.com is a so-called
virtual alias domain. If you omit
this setting then Postfix will reject mail (relay access denied)
or will not be able to deliver it (mail for example.com loops back
to myself).
NEVER list a
virtual alias domain name as a
mydestination
domain!
-
Lines 3-11: The /etc/postfix/virtual file contains the
virtual aliases. With the example above, mail for [email protected]
goes to the local postmaster, while mail for [email protected] goes
to the remote address joe@somewhere, and mail for [email protected]
goes to the remote address jane@somewhere-else. Mail for all other
addresses in example.com is rejected with the error message "User
unknown".
-
Line 10: The commented out entry (text after #) shows how
one would implement a catch-all virtual alias that receives mail
for every example.com address not listed in the virtual alias file.
This is not without risk. Spammers nowadays try to send mail from
(or mail to) every possible name that they can think of. A catch-all
mailbox is likely to receive many spam messages, and many bounces
for spam messages that were sent in the name of [email protected].
Execute the command "postmap /etc/postfix/virtual" after
changing the virtual file, and execute the command "postfix
reload" after changing the main.cf file.
More details about the virtual alias file are given in the
virtual(5) manual page, including multiple addresses on the right-hand
side.
