Re: [OT] Seeing increase in smtp concurrency ?

Rajkumar S wrote:
> Hi,
>
> Does any one seeing increasing smtp concurrency for the past couple of
> weeks? I run couple of (qmail/simscan/spamassassin) mail servers and
> all experience the same problem. The spam does not increase, but this
> is hogging my mail servers. Probably a new crop of spamming tools?
>
> I am attaching one qmail-mtrg graph that shows the problem.
>
> http://img403.imageshack.us/img403/2224/smtpmonthyq4.png

Yeah, two weekends ago our mail servers got absolutely slammed with connections that were left open. They'd get rejected, and then leave the connection open for a while, then try again, and so on.

Our count of exim processes per server went up from our already higher-than-it-recently-used-to-be 500 to around 1,000. This continued on monday, climbing to around 1300. Restarting exim and killing off these old connections would only relieve it for ten minutes or less. When it hit 1500, we moved a few of our rbls to the connect phase, which brought it down to about 150 exim procs. Yeesh...

-- 
Gus