I don't know if this is the right place to ask this kind of question but here goes.
I have 3 IPs on my server, which I'm running for shared hosting. The main shared IP gets blacklisted sometimes, obviously sometimes an account is compromised and it sends out spam so the IP gets blacklisted, that I can understand, I try to limit it as much as I can but where I am from, it is really hard to convince a customer to update their CMS so they don't keep getting hacked.
And that goes for most accounts so no point of kicking them all really : )
The strange thing though is, I have an important account on a dedicated IP, which I thought will solve the blacklisting problem for him! To my surprise this IP address got blocked as well even though it did not send out any spam, maybe only because it is on the same subnet?? Or how do those blacklists end up blocking my other IP?
Also if you guys can point me to the right direction as to what measures I should take to prevent this from happening again and again, I thought clamd or spamassassin should work to prevent spam, but obviously they work for incoming messages not outgoing messages.
I decided to take a somewhat drastic measure, I will setup a script that runs every hour or so, count the number of messages in the queue for each domain, and if the number exceeds X amount of messages, the domain will be blocked from sending email until reviewed.
Is there anything I can do to actually DETECT outgoing spam, so it does not have to flood the queue.
Thanks