Subject: Re: Sendmail delivery funny
To: None <email@example.com,>
From: Julian Coleman <firstname.lastname@example.org>
Date: 11/05/2000 17:01:34
> please provide the folloing information.
> - what do you mean by "TTL 0"?
tcpdump shows :
18:30:56.735349 coris.demon.co.uk.49269 > tele-post-20.mail.demon.net.smtp: S [tcp sum ok] 1004049898:1004049898(0) win 16384 <mss 1484> [ttl 0] (id 3455)
> - can you tell us which domain is the destination? (so that we can see
> the MX records for the destionation).
This mail was going to ncl.ac.uk. I have :
in my sendmail.mc, so I only see AAAA (no reply) and A lookups for the relay.
Also, this happens to every mail message that goes out.
> - show us the result of "netstat -an" during the delayed connection.
> (otherwise, you are not sure if the first trial is to IPv6
> destination or not)
Well, I wasn't 100% sure, but ktrace of sendmail showed :
10567 sendmail CALL socket(0x18,0x1,0)
10567 sendmail RET socket 6
10567 sendmail CALL __sigprocmask14(0x1,0,0x82b88)
10567 sendmail RET __sigprocmask14 0
10567 sendmail CALL __sigaltstack14(0,0xefffa950)
10567 sendmail RET __sigaltstack14 0
10567 sendmail CALL connect(0x6,0xefffaa78,0x1c)
10567 sendmail RET connect -1 errno 60 Connection timed out
10567 sendmail CALL close(0x6)
for each failed connection and domain 0x18 is INET6. As soon as it does :
10567 sendmail CALL socket(0x2,0x1,0)
the mail gets sent.
`netstat -an` shows (lots of output but I assumed you're interested in) :
tcp6 0 0 ::ffff:18.104.22.168344 ::ffff:22.214.171.124 SYN_SENT
Also, `fstat` shows :
root sendmail 11032 8* internet6 stream tcp f0429600 [::ffff:126.96.36.199]:49344 <-> [::ffff:188.8.131.52]:25
> if you do not have IPv6 default route, even if sendmail attempts to
> connect to IPv6 destination, it will fail right away and there should
> be no problem.
`netstat -rn` shows the following IPv6 routes on ppp0 :
fe80::%ppp0/64 link#3 UC 0 0 1524 ppp0
fe80::a00:20ff:fe09:6caf%ppp0 ::1 UH 0 0 33228 lo0
ff02::%ppp0/32 link#3 UC 0 0 1524 ppp0
My other computer also runs NetBSD