In webmin >Severs > Postfix mail server > Edit config file, change this small line-
inet_interfaces = all
#inet_interfaces = $myhostname
#inet_interfaces = $myhostname, localhost
#inet_interfaces = localhost
The significance is- if you don’t uncomment inet_interfaces =all, your server is completely isolated from the network. It won’t listen other than the server or localhost. In order to check if the settings are ok- you need to connect to your server from a networks pc. Open ‘cmd’ in your pc and type-
telnet X.X.X.X 25
If something returns- then its ok, else if it’s Unable to connect, you need to make the above changes I’ve mentioned.
Postfix on most systems is very nearly ready for use as the mail server for the Virtual Servers module. The only thing missing is the configuration for a virtual mapping database and, if using quotas, moving the spool directory to the same partition that user data lives on. The first can be added easily using Webmin. Browse to Postfix:Virtual Domains. Enter a type of database, and a filename for the virtual map database into the Domain mapping lookup tables field. Generally, this will be something along the lines of hash:/etc/postfix/virtual. In this example the type is a dbm hash, and the filename is virtual in the /etc/postfix directory. Save and apply your change.
Next, you’ll need to move your mail spool to the /home partition. Browse to the Postfix:Local Delivery module. Edit the Spool directory option and enter /home/mail. Save and Apply your changes.
It is useful to choose mail as the subdirectory here, because there will already exist a mail user on most systems and so there is no way to accidentally create a new user that would end up getting your mail spool as their home directory! If you don’t use Red Hat Linux, you should probably first check to be sure there is a user named mail on your system (I believe most UNIX systems do have a user of this name).
In order for POP or IMAP to work, those servers will need to know how to find the mail spool. The easiest thing to do for this is probably to create a symbolic link from /var/spool/mail to /home/mail. The command to do this:
# ln -s /home/mail /var/spool/mail