Restrict incoming mail servers

[Lenz Weber]

Hello,
we have an external SpamFilter service (expurgate) pre-filtering our incoming mail for us. After they have filtered and marked mail, it is forwarded to us from a few servers with known IP addresses. Thus, we only want to receive incoming emails from these few IP addresses. This would be fine with just a firewall rule blocking smtp port for all other IPs.

But of course, we also want our users to send emails - using our server directly, with authentification, which uses the same port.

Is there a way to block incoming non-authentificated emails from all but a few whitelisted IPs using plesk?

 

[Faris Raouf]

Your users should use port 587 instead of 25 for sending authenticated email. You can enable port 587 by ticking the "submission" box in the email settings page.

In that way you can firewall port 25 to only allow your spamfiltering service to connect, and allow all your customers to use port 587 for sending authenticated email.