[Mimedefang] Network issues causing broken pipe errors (and subsequent tempfails)?

[David F. Skoll]

On Fri, 27 Feb 2004, Michael Sims wrote:

> Basically I say all this to ask a question.  Is it possible that this
> message is taking so long to transfer that the MD slave is dying before it
> is fully received, and this is what is causing the broken pipe error?

Nope.  No slave is even involved until the message has been received in
its entirety.  (A C thread inside mimedefang just spools the message
into /var/spool/MIMEDefang; only when it's all there is a slave activated.)

The multiplexor is designed so that when a slave needs to do work, it
has all the information at its disposal, and does not need to wait for
anything from the SMTP peer.  This makes it hard for an adversary to keep
a slave busy for an arbitrarily long time.  (Of course, this can be achieved
in other ways by crafting a message that beats up on SpamAssassin's regular
expressions, but it can't be done because of network characteristics.)

> I am
> using the "-l" option to the multiplexor and it is not logging anything for
> this message,

Right.  The multiplexor knows nothing about the message until it has been
completely collected.  My guess is that there's a libmilter timeout somewhere
that's terminating the milter thread.  See
http://www.sendmail.com/partner/resources/development/milter_api/smfi_settimeout.html

Regards,

David.