{"id":122,"date":"2015-06-14T12:29:51","date_gmt":"2015-06-14T12:29:51","guid":{"rendered":"http:\/\/star.genuinewebhost.com\/~linuxguru\/tutorial\/?p=122"},"modified":"2025-07-10T01:32:04","modified_gmt":"2025-07-10T01:32:04","slug":"configuring-postfix-virtual-mail-domain","status":"publish","type":"post","link":"http:\/\/shijuvarghese.com\/?p=122","title":{"rendered":"Configuring postfix virtual mail domain"},"content":{"rendered":"

This is part of the Postfix documents series, continuation of “Accessing a dovecot imap server using SquirrelMail”. One should complete the initial steps in these docuemtns to make this work.<\/p>\n

Create a user to manage postfix
\n]# useradd postfixuser<\/strong><\/p>\n

Find the GID and UID.<\/p>\n

]# cat \/etc\/passwd | grep postfixuser<\/strong>
\npostfixuser:x:1003:1003::\/home\/postfixuser:\/bin\/bash<\/p>\n

]# cat \/etc\/group | grep postfixuser<\/strong>
\npostfixuser:x:1003:<\/p>\n

In my example the UID and GID of the user postfixuser is 1002.<\/p>\n

Edit the main config file.
\n]# vi \/etc\/postfix\/main.cf<\/strong><\/p>\n

Add the below lines:<\/p>\n

virtual_mailbox_domains = \/etc\/postfix\/vhosts<\/em>
\nvirtual_mailbox_base = \/home\/postfixuser<\/em>
\nvirtual_mailbox_maps = hash:\/etc\/postfix\/vmaps<\/em>
\nvirtual_minimum_uid = 1000<\/em>
\nvirtual_uid_maps = static:1003<\/em>
\nvirtual_gid_maps = static:1003<\/em><\/p>\n

List the domains that you wish to host.
\n]# vi \/etc\/postfix\/vhosts<\/strong>
\nAdd the following lines listing examples of domains:<\/p>\n

mydomain_1.com<\/em>
\nmydomain_2.com<\/em><\/p>\n

We should create a file that maps where the mails of each user in each domain will be hosted:
\n]# vi \/etc\/postfix\/vmaps<\/strong><\/p>\n

user1@mydomain_1.com mydomain_1.com\/user1\/<\/strong><\/span><\/em>
\nuser2@mydomain_1.com mydomain_1.com\/user2\/<\/strong><\/span><\/em>
\nuser1@mydomain_2.com mydomain_2.com\/user1\/<\/strong><\/em>
\nuser2@mydomain_2.com mydomain_2.com\/user2\/<\/strong><\/span><\/em>
\nNow we need to convert the vmaps text file into a hash file by running the following command:
\n]# postmap \/etc\/postfix\/vmaps<\/strong><\/p>\n

Create folders for each domain in the \/home\/postfixuser folder<\/p>\n

]#\u00a0mkdir \/home\/postfixuser\/mydomain_1.com<\/strong><\/p>\n

]#\u00a0mkdir \/home\/postfixuser\/mydomain_2.com<\/strong><\/p>\n

For testing let us five the folder permission as chmod 777<\/p>\n

]# chmod 777 \/home\/postfixuser\/*<\/strong><\/p>\n

Restart the postfix server
\n]# systemctl restart postfix<\/strong><\/p>\n

Now let us send a mail to one of the user using a telnet session:<\/p>\n

]# telnet localhost 25<\/strong>
\nTrying ::1…<\/em>
\nConnected to localhost.<\/em>
\nEscape character is ‘^]’.<\/em>
\n220 <My FDQN> ESMTP Postfix<\/em>
\nEHLO <My FDQN><\/em>
\n250-<My FDQN><\/em>
\n250-PIPELINING<\/em>
\n250-SIZE 10240000<\/em>
\n250-VRFY<\/em>
\n250-ETRN<\/em>
\n250-ENHANCEDSTATUSCODES<\/em>
\n250-8BITMIME<\/em>
\n250 DSN<\/em>
\nMAIL FROM:root@<My FDQN><\/em>
\n250 2.1.0 Ok<\/em>
\nRCPT TO:user2@mydomain_1.com<\/em>
\n250 2.1.5 Ok<\/em>
\nDATA<\/em>
\n354 End data with <CR><LF>.<CR><LF><\/em>
\nSubject:Hello there<\/em>
\nThis is Shiju<\/em>
\n.<\/em>
\n250 2.0.0 Ok: queued as 7E68A6D409E2<\/em>
\nquit<\/em>
\n221 2.0.0 Bye<\/em><\/p>\n

 <\/p>\n

Now check if the files got created in the user’s name<\/p>\n

]# ls -l \/home\/postfixuser\/mydomain_1.com\/<\/strong>
\n-rw——- 1 postfixuser postfixuser 565 Sep 14 18:40\u00a0user2<\/em><\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

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