[Mimedefang] nasty multiplexor death

[Adam Lanier]

Running: sendmail 8.12.11, mimedefang 2.42 and spamassassin 2.63 on RedHat 8. Platform is a HP (Compaq) DL 380 dual Xeon 2.8Ghz processors w/ 1Gb RAM.  MD is limited to 24 concurrent processes and max queue depth of 20.

Have been having a problem recently where the following errors will be logged:

Apr 27 13:47:31 krusty mimedefang[27573]: mfconnect: Error communicating with multiplexor

Looks like what happens is I get bombarded by a huge amount of simultaneous connections at once, the multiplexor maxes out processes and queueing, the queued messages start timing out and the multiplexor starts generating these types of errors:

Apr 27 03:52:10 krusty sendmail[11446]: i3R5p4v0011446: Milter (mimedefang): to error state

Usually, I need to restart the multiplexor to recover from this.  These machines are my external relays so they do get hit by spammers hard.  I have these sendmail settings in place to protect the server:

define(`confQUEUE_LA', `12')dnl
define(`confREFUSE_LA', `18')dnl
define(`confCONNECTION_RATE_THROTTLE', `3')dnl

and I've added the following as of today: 

define(`confMAX_DAEMON_CHILDREN', `24')dnl

Has anyone else seen this type of behavior and are my settings in order?  I'm thinking I might tweak the queue_la/refuse_la settings down a bit.

Am I totally off here with regards to what is causing my multiplexor to croak?

One final thing, I have been playing with a script that uses the MX_NOTIFIER feature, assuming that I would see these errors in the output from the multiplexor and thus be able to programmatically reqct to them but I see no such output.  Should I be seeing this type of output and, if so, what would it look like?

-- 
Adam Lanier
Bernard L. Madoff Investment Securities LLC