[Mimedefang] Reject 451 (Please try again later) messages

[Bill Randle]

On Fri, 2003-06-20 at 18:49, David F. Skoll wrote:
> On Fri, 20 Jun 2003, Bill Randle wrote:
> 
> > My most recent conclusion, based on some other mail log messages I
> > was seeing is that the mail server box is just plain underpowered
> > and can't keep up with the incoming flood of email (1000-1200/hr).
> 
> 1200/hr is not that much at all.  What was your system configuration?

Based on what others have said, it doesn't seem like a huge load
to me, either. System configuration was dual 400 MHz Xenon,
Intel 440BX motherboard, 768 MB RAM, UDMA 33 HDD, Intel EEPRO100
Ethernet card. Kernel 2.4.19-33mdksmp, MIMEDefang-2.34-BETA-5,
SpamAssassin-2.60 CVS.

With all network tests and bayes disabled, it still couldn't
keep up.

> I'm working on 2.34-BETA-7 that has an experimental feature called
> "queueing".  If all slaves are busy, we allow requests to queue (up to
> a queue size limit, and only for a limited time period.)  New
> connections get rejected early on, but established ones are given a
> bit of extra queue time in the hopes they'll succeed.  I'd be
> interested in hearing if this helps for heavily-loaded servers.

I'd be happy to test it, once it's available.

> > I ended up disabling the spam filtering temporarily due to
> > customer complaints of being unable to send email. (Uhg!)
> 
> You should always use a separate box (or at least a separate Sendmail
> daemon that doesn't use MIMEDefang) for customer's mail submission.

We have set this up now, also, but it takes a while to transition users
to the new address.

	-Bill