[Mailman-Users] Bounces being detected as spam/virus sending rate

[Steven D'Aprano]

Hi,

I run a mailing list of about 1-2 thousand subscribers for announcements 
only. My ISP has started sending me automated messages claiming that 
there is a high spam/virus sending rate from my IP address. It took me a 
long time to get a straight answer from them, but eventually they told 
me that they are not triggering on me sending email, but on the number 
of bounces that come back.

My setup is that outgoing mail goes through the ISP's mail server (that 
was their recommendation) but incoming mail comes directly to me. I send 
out an announcement, and a few days or a week later I get an automated 
message from the ISP suggesting I might be sending spam or a virus and 
pointing me to the usual generic Windows anti-virus solutions.

All my computers here are Linux, so while it is not impossible that I 
have been infected and am now part of a spammer's botnet, I think it's 
unlikely.

I receive unhandled bounce notifications (no more than a handful of 
those, which I then manually remove) and see notifications of addresses 
that are removed for excessive bouncing, again no more than a handful at 
a time. How can I see a list of members set to No Mail for bouncing?

Can you suggest anything I can do to avoid triggering the ISP's system? 
(A hard question, I know, since we don't know precisely what triggers 
it in the first place.)


-- 
Steve