m.roth@5-cent.us wrote:
Mike wrote:
Simon Billis wrote:
<snip>>
I run a few sendmail servers that run MailScanner/Spamassassin/sendmail (current versions) on Centos 5.4 and Centos 4.8 These boxes accept mail for a large number of domains (6000+) scan the mail removing spam and then forward the ham to another server for delivery. I am attempting to stop any backscatter that these servers cause by only accepting mail for specific users@domain or for domains with a catch-all account.
running make -C /etc/mail but this has no effect on the sendmail.cf file. My
Does it not give output? Have you tried adding -d?
<snip> > Another would be to use MimeDefang as the framework instead of > mailscanner. It has an option to check recipient addresses via smtp to > the delivery servers before accepting. You may have to write a snippet > of perl to get that right for multiple domains (that's a feature...). > This is less efficient but works in real time against the addresses that > will be accepted for delivery.
I would question how "real time" that would be for every email for 6k+ domains. If a few have a large client base, or are expecting responses from a mass emailing, it might start to take a *while*, unless you've got pretty heavy duty equipment and networking.
It's the same thing the downstream server is going to have to repeat in just a moment anyway, but this time it doesn't have to do the other steps. If you are close to capacity already it might push you over the edge - and be worth scripting a way to maintain that frontend virtuser table that makes it a near-instant hash lookup for the relay sendmail. But for the relay it will be a win either way to avoid the much heavier load of spam-scanning stuff to invalid recipients and making the downstream servers construct bounces.