[afnog] Two mail servers in the same domain

[SM]

At 10:31 12-12-2008, Kone wrote:
>I have a mail server running under postfix and dns server in my 
>network. I want to install an other mail server to backup mails.
>Any particular configuration to do in the second mail server or in the dns ?

You can have a mail server acting as a backup in case the first mail 
server is unreachable.  There should be two MX records in DNS for 
example.com with the lower number giving a higher priority:

     MX 5  mail1.example.com.
     MX 10 mail2.example.com.

Use the relay_domains setting in the Postfix configuration to 
specific the domain on the second mail server.

>I plan to make a backup using rsync with cron.

Although you can backup the mailboxes, you won't be able to 
synchronize the mail on both servers.

Regards,
-sm