This is quite simple, and with a very simple setup, and does not require that much, since we do not need to send out e-mails from clients from this server, or use ASMTP. I find that MySQL is not needed here, but could be used. I will use normal flat files, since the number of domains to run a backup for is most likely a rather small number.
This setup can be editet to run all times of different checks, antivirus etc. Normally you would make sure that the setup is exactly the same on both the primary MTA, and the backup. It hardenens the systems, and should reduce spam, and unwanted traffic. Create public DNS entries. Remember to create an MX record with an lower priority than the primary mail server, or else this will not work!
Example:example.com. 43200 IN MX 10 mail.example.com. example.com. 43200 IN MX 20 backup.example.com.
After this these two records are created with A records pointing to different IPs (different servers). Continue reading “Perfect Backup MX using Postfix” »