There are 2 anti-spam setups that are used by IPServerOne.

Below is a guide on how to setup the FREE version of incoming anti-spam for any domain on Linux servers.

I will be using fabulousmom.com and antispam-300.small-dns.com as an example.

Firstly, log in to the anti-spam server via SSH.

Then, edit the file below to add the specified domain and IP address of their mailserver.
[cc]
vi /etc/exim/manual-routes
[/cc]
[cc]
fabulousmom.com: 14.102.146.5
[/cc]
Then, edit the file below to add the domain name.
[cc]
vi /etc/exim/relay-domains
[/cc]
[cc]
fabulousmom.com
[/cc]
Now that both those files have been edited, we would need to point the MX record for the domain to the anti-spam server as below:
[cc]
0 antispam-300.small-dns.com 103.21.180.36
[/cc]
Once that’s been done, we would need to allow 4-12 hours for DNS propagation.

This would mean that incoming emails will be sent to the anti-spam server IP 103.21.180.36 first.

From there, the manual-routes and relay-domains will come into play, and the email will be sent to their respective mail servers.