On Sat, Aug 04, 2012 at 09:11:07AM -0500, Stan Hoeppner wrote:
> Would someone kindly point me to the docs that describe the behavior of
> smtpd socket open time in relation to clients that do connection caching?
$ postconf -d smtpd_timeout
smtpd_timeout = ${stress?10}${stress:300}s
> I've been assisting in a troubleshooting effort. A sendmail/mailman
> based list server is opening more than 4 concurrent connections to my MX
> even when it has less than a half dozen messages to deliver, which
> suggests connection caching on their end is not working properly.
Sendmail's connection cache is rather crude. The fact that it is
crude is unavoidable, Sendmail lacks a queue manager, scache daemon,
... so connections are cached in process, and thus the probability
of actual re-use is lower, and the TTLs are longer. IMHO the whole
thing is a bad idea on an Internet-facing MTA (which delivers mail
to a broad list of destinations), it may make some sense on an internal
network with a small number of peer MTAs.
--
Viktor.
