Date: Wed, 28 Aug 2002 13:48:50 -0400 From: Jim Brown <jpb@sixshooter.v6.thrupoint.net> To: freebsd-hackers@FreeBSD.ORG Cc: freebsd-questions@FreeBSD.ORG Subject: Re: why does this sendmail connection take so long? Message-ID: <20020828174850.GB77792@sixshooter.v6.thrupoint.net> In-Reply-To: <3D6CC8E1.8800.896A6F03@localhost> References: <003e01c24a2b$31eb7980$3301010a@MIKELT> <3D6CC8E1.8800.896A6F03@localhost>
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* Dan Langille <dan@langille.org> [2002-08-28 13:01]: > On 22 Aug 2002 at 18:28, Michael Scheidell wrote: > > > ----- Original Message ----- > > From: ""Dan Langille"" <dan@langille.org> > > Newsgroups: local.freebsd.hackers > > Sent: Thursday, August 22, 2002 1:41 PM > > Subject: why does this sendmail connection take so long? > > > > > > > I'd normally attribute this problem to DNS, but I can't track down > > > what DNS problem is occuring. Note the lag between the first event > > > and the next. Any suggestions? > > > > might be identd (port 113) > > After some testing, I'm inclined to think it's not ident. The > network in question is behind a firewall which is doing NAT. Two > boxes do not exibit the problem. Two do. All are FreeBSD 4.6-stable > created from same source snapshot. > > I've tested this from several boxes behind my firewall each time > emailing to a box outside the firewall. The test was: > > echo 'hi there' | mail dan@m20.example.org > > The two boxes which exibit the probem are the DNS server and the > firewall. Mail sent from those boxes exhibit identical delays, > namely a 75 second lag between the first and second event (see below > for an example; note that I've changed the real domain to > example.org). I'm not sure whether this indicates a problem on the > sending or receiving end. I suspect sending. But what the problem > is I'm not sure yet. > > I've been running "tcpdump -i lo0 port 53" to see if I could find > anything suspect in there, but I didn't. BTW, what would I be > looking for if the above delay is caused by DNS? I don't think you can see 127.0.0.0 traffic this way, BICBW. In general you should see less than a 2 second reply to any DNS query if everything is configured correctly. Most replys are less than .5 seconds even on a fairly busy network. > > Thanks. > > Aug 28 12:07:24 xeon sendmail[66323]: g7SG7O7G066323: from=dan, > size=37, class=0, nrcpts=1, > msgid=<200208281607.g7SG7O7G066323@xeon.example.org>, > relay=dan@localhost > > Aug 28 12:08:39 xeon sm-mta[66507]: g7SG8dvj066507: > from=<dan@xeon.example.org>, size=351, class=0, nrcpts=1, > msgid=<200208281607.g7SG7O7G066323@xeon.example.org>, proto=ESMTP, > daemon=MTA, relay=localhost [127.0.0.1] > > Aug 28 12:08:40 xeon sendmail[66323]: g7SG7O7G066323: > to=dan@m20.example.org, ctladdr=dan (1000/1000), delay=00:01:16, > xdelay=00:01:16, mailer=relay, pri=30028, > relay=localhost.example.org. [127.0.0.1], dsn=2.0.0, stat=Sent > (g7SG8dvj066507 Message accepted for delivery) > > Aug 28 12:08:42 xeon sm-mta[66509]: g7SG8dvj066507: > to=<dan@m20.example.org>, ctladdr=<dan@xeon.example.org> (1000/1000), > delay=00:00:03, xdelay=00:00:02, mailer=esmtp, pri=30342, > relay=m20.example.org. [216.187.106.227], dsn=2.0.0, stat=Sent (Ok: > queued as 169F57A11) OK, I'm going to try to analyze this *without* my Sendmail tome handy (it's on another continent)... Looks like you've got sendmail on the local machine to first relay to host localhost.example.org probably in /etc/mail/sendmail.cf. I'd suggest just setting your relayhost to the firewall machine. (And set the firewall relayhost to nothing- let him do final transfer.) No- I don't remember quirky sendmail variable- web over to sendmail.org or read the config file notes. Another test you should try is to just simulate the mail exchange via telnet. Run through the protocol (helo, mail from:, rcpt to:, data) and see performance. Also check how long it takes to close the tcp connection. I think that is also tunable via sendmail.cf Getting the split mail setup working correctly is tricky, but there are some examples in the big Sendmail book. Probably should move this to -questions... Hope this helps, jpb === [snip] To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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