8 messages in net.sourceforge.lists.courier-usersRe: [courier-users] Server hangup aft...
FromSent OnAttachments
Avinash SultanpurFeb 22, 2007 10:19 pm 
jero...@free.frFeb 23, 2007 12:29 am 
Avinash SultanpurFeb 23, 2007 2:32 am 
Sam VarshavchikFeb 23, 2007 3:59 am 
jero...@free.frFeb 23, 2007 7:08 am 
Gordon MessmerFeb 23, 2007 8:29 am 
Jérôme BlionFeb 23, 2007 12:29 pm 
Gordon MessmerFeb 23, 2007 1:07 pm 
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Subject:Re: [courier-users] Server hangup after exceeding maximum active connectionsActions...
From:Gordon Messmer (yiny@eburg.com)
Date:Feb 23, 2007 8:29:33 am
List:net.sourceforge.lists.courier-users

jero@free.fr wrote:

It looks like a DDoS...

No, not really. The reason that courier specifies a maximum number of connections is specifically to avoid a DOS type attack. Opening 30 SMTP connections isn't going to bring a server to its knees.

Something non-courier related is probably causing the machine to overload, which is probably why connections to the SMTP server stack up. The connections are a symptom of the problem, not the cause. You're going to need to engage in good, old-fashioned unix debugging to figure out what's running away on your server. Leave some root terminals logged in so that when the machine stops accepting logins, you can see whether established sessions still work, and proceed from there.

Spammers would become more aggressive than they already were in the past?

What benefit would spammers get from bringing SMTP servers down with DOS style attacks? They make their money by sending mail. If they take recipient servers down, they can't send more mail.