From: "Steve Simon" <steve@quintile.net>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] smtp dns failure: mx lookup
Date: Tue, 3 Jan 2006 12:13:58 +0000 [thread overview]
Message-ID: <5822959c74cc60ab78dec36a37e18d30@quintile.net> (raw)
In-Reply-To: <9bef2a2dfb71042935f1e86c22f57f1c@tombob.com>
> echo smtp.comcast.net |ndb/dnsquery >/dev/null
Yep, this is what I do too, I followed it through smtp(8)
a while ago and came to the conclussion it was a
caching problem in dns(8).
looking at /sys/src/cmd/upas/smtp/mxdial.c:163
smtp looks up "smtp.comcast.net mx" but receives "dns failure"
and gives up.
dns should reply "resource does not exist" which would prompt
smtp to retry with "smtp.comcast.net ip" which will succeed.
If you force the "smtp.comcast.net ip" into dns's cache using
the manual query above then it replies "resource does not exist"
correctly and smtp completes as it should.
After some time the entry ages out of the cache and the
problem reappears.
I used ndb/dnsdebug to prove that it was not a dns config problem
and put it on my To-Do list, where it has gathered dust.
A little more info, but no fix - only the same old bodge, sorry
-Steve
next prev parent reply other threads:[~2006-01-03 12:13 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-03 1:50 greg scott
2006-01-03 9:31 ` Robert Raschke
2006-01-03 12:13 ` Steve Simon [this message]
2006-01-03 12:18 ` erik quanstrom
2006-01-03 14:39 ` Russ Cox
2006-01-04 2:28 ` erik quanstrom
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5822959c74cc60ab78dec36a37e18d30@quintile.net \
--to=steve@quintile.net \
--cc=9fans@cse.psu.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).