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

[Bill Randle]

On Fri, 2003-06-20 at 17:09, Justin Shore wrote:
> Bill,
> 
> Did you ever get your 451 errors sorted out?  If so, could you summarize 
> for the list?  I too am experiencing them.  It's gotten to the point where 
> my Sendmail and MD installation is all but unuseable and extremely 
> unreliable.  I have a cronjob restart MD and Sendmail every 5 minutes to 
> cope with the matter.  I've even disabled AV checks in their entirety.  If 
> you found a solution, I'd love to hear what it was.
> 
> Justin

Justin,

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).
I ended up disabling the spam filtering temporarily due to
customer complaints of being unable to send email. (Uhg!)

My suspicion is that the system was becoming I/O bound, so we
installed a fast SCSI-3 disk today just for mail and mail log
files. (/var/spool/MIMEDefang was already tmpfs'd so should be
fast.) I'll be reconfiguring things tomorrow and will let you
know how it goes.

A colleague with about 3x the number of customers as us apparently
has three boxes dedicated to spam filtering. I don't know yet what
software they're using, but the hardware platform is typically
dual processor Sun Ultra systems running Solaris.

	-Bill