[9945] in bugtraq
Re: Microsoft's SMTP service broken/stupid
daemon@ATHENA.MIT.EDU (Alan Brown)
Wed Mar 17 22:00:10 1999
Date: Wed, 17 Mar 1999 19:47:52 +1300
Reply-To: Alan Brown <alan@MANAWATU.GEN.NZ>
From: Alan Brown <alan@MANAWATU.GEN.NZ>
X-To: Chris Adams <cadams@RO.COM>
To: BUGTRAQ@NETSPACE.ORG
In-Reply-To: <19990314204930.C3493@ro.com>
On Sun, 14 Mar 1999, Chris Adams wrote:
> Well, that has been fine, but now Microsoft's SMTP service comes along.
> When it gets that temporary error (for invalid reverse DNS), it tries
> again. Fast. Like, right away, with no delay. This bogs down our
> servers a bit, especially the extra logging load, but eventually they go
> away.
>
> Yesterday, we got hit by four different servers running Microsoft's
> software. One attempted delivery nearly 200,000 times, and the other
> three attempted to 30,000-40,000 times each. This on a server that
> usually sees ~40,000 messages a day. This filled up our logs, bogged
> everything down, and basically killed us.
What's needed is judicious tuning of these configuration items:
# load average at which we just queue messages
O QueueLA=8
# load average at which we refuse connections
O RefuseLA=12
The above two default to 8 and 12
# maximum number of children we allow at one time
O MaxDaemonChildren=12
# maximum number of new connections per second
O ConnectionRateThrottle=3
If the above two aren't defined, there are no limits.
Also useful for load control are these two items:
# deliver each queued job in a separate process?
#O ForkEachJob
# single thread deliveries (requires HostStatusDirectory)?
#O SingleThreadDelivery
AB
