Backscatter IP Blacklist due to NDRs

symmcom

Renowned Member
Oct 28, 2012
1,078
26
68
Calgary, Canada
www.symmcom.com
Hello,

The PMG is trying to send out lots of Bounce reports to bogus destination we are receiving SPAM emails from. This is putting our IP address into Backscatter IP Blacklist and causing some issue when users are trying to send out emails. Some destination servers rejecting emails coming out from the PMG.

One way to stop this is by disabling Bounce reports. I really dont want to do that since that will also apply to legit emails trying to come to us. Even if i wanted to do that where is that option in PMG?

Whats backscatter score should be for this and how to better protect PMG from this sort of things?
 

dietmar

Proxmox Staff Member
Staff member
Apr 28, 2005
16,577
336
103
Austria
www.proxmox.com
One way to stop this is by disabling Bounce reports.
Those report are required by the SMTP protocol, so IMHO it would be a bad idea to disable them...

I guess you could do it by modifying postfix master,cf bounce service, but that is highly discouraged
and I never really tried that.
 

heutger

Active Member
Apr 25, 2018
748
201
43
Fulda, Hessen, Germany
www.heutger.net
Hello,

The PMG is trying to send out lots of Bounce reports to bogus destination we are receiving SPAM emails from. This is putting our IP address into Backscatter IP Blacklist and causing some issue when users are trying to send out emails. Some destination servers rejecting emails coming out from the PMG.

One way to stop this is by disabling Bounce reports. I really dont want to do that since that will also apply to legit emails trying to come to us. Even if i wanted to do that where is that option in PMG?

Whats backscatter score should be for this and how to better protect PMG from this sort of things?
You should check, why your system is sending bounce reports. Usually (and that's the reason why they are seen as backscattering and you're blacklisted therefor) that should not occur. Your server should verify recipients already on connection and reject connection, if the recipient is not available. So check first, which setting let bounces coming up and try to resolve this instead of disabling them.
 

About

The Proxmox community has been around for many years and offers help and support for Proxmox VE and Proxmox Mail Gateway. We think our community is one of the best thanks to people like you!

Get your subscription!

The Proxmox team works very hard to make sure you are running the best software and getting stable updates and security enhancements, as well as quick enterprise support. Tens of thousands of happy customers have a Proxmox subscription. Get your own in 60 seconds.

Buy now!