On 12/30/2010 07:22 PM, Brent Gardner wrote:
I've run into an issue where clients are sending us emails from
Outlook/Exchange that aren't coming through. The connection is dropped
without any good indicator on the toaster as to the reason.
The clients in question route their outbound mail through Google/Postini
or GoDaddy. They're getting 4.4.2 or 4.4.7 errors from their Exchange
servers.
I set a full-log-dir and set log-level=excessive in spamdyke and didn't
get any detail about the connection state except 'CLOSED' when the
connection dropped. I noticed, however, that in every case, the
connection dropped while the remote end was transmitting a 'References:'
header.
One client sent a bounce email to us which contained full headers of the
original message, and I noticed that the 'References:' header was over
1024 characters long. Could this be the cause? If so, how do I work
around it? Is there somewhere I can tell qmail to accept headers longer
than 1024 characters? Thorough googling has yielded nothing helpful.
I did some tests. I generated messages with 'References:' headers that
were more than 1024 characters long and less than 1024 characters long.
Every time, the messages with longer headers didn't go through, and the
messages with shorter headers went through fine.
I used Blat to send the messages. Failed messages always got this error:
Error: Connection to server was dropped.
Message not accepted by server
connection::put_data() unexpected error from send(): 10054
Error: Error sending data.
Error: Connection to server was dropped.
Never an error message in the qmail smtpd log.
I tried this both with spamdyke and without.
My environment:
32-bit CentOS 5.3 running as a guest on a 64-bit VMware Server 2 on
64-bit CentOS 5.3
spamdyke 4.0.10+TLS+CONFIGTEST+DEBUG, installed using qtp-install-spamdyke
autorespond-toaster.i386 2.0.4-1.3.6
clamav-toaster.i386 0.95.2-1.3.30
control-panel-toaster.noarch 0.5-1.3.7
courier-authlib-toaster.i386 0.59.2-1.3.10
courier-imap-toaster.i386 4.1.2-1.3.10
daemontools-toaster.i386 0.76-1.3.6
ezmlm-cgi-toaster.i386 0.53.324-1.3.6
ezmlm-toaster.i386 0.53.324-1.3.6
isoqlog-toaster.i386 2.1-1.3.7
libdomainkeys-toaster.i386 0.68-1.3.6
libsrs2-toaster.i386 1.0.18-1.3.6
maildrop-toaster.i386 2.0.3-1.3.8
maildrop-toaster-devel.i386 2.0.3-1.3.8
qmail-pop3d-toaster.i386 1.03-1.3.20
qmail-toaster.i386 1.03-1.3.20
qmailadmin-toaster.i386 1.2.12-1.3.8
qmailmrtg-toaster.i386 4.2-1.3.6
qmailtoaster-plus.noarch 0.3.1-1.4.15
qmailtoaster-plus.repo.noarch 0.2-2
ripmime-toaster.i386 1.4.0.6-1.3.6
simscan-toaster.i386 1.4.0-1.3.8
spamassassin-toaster.i386 3.2.5-1.3.17
squirrelmail-toaster.noarch 1.4.19-1.3.15
ucspi-tcp-toaster.i386 0.88-1.3.9
vpopmail-toaster.i386 5.4.17-1.3.7
vqadmin-toaster.i386 2.3.4-1.3.6
All mail (that passes tests) is forwarded to an internal Exchange server.
All communications between the toasters and outside world or the
Exchange server go through a Cisco ASA.
Brent Gardner
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Wow, Brent. This is one of the nicest, most thorough problem reports
I've seen. Nice work.
From the LWQ page (http://www.lifewithqmail.org/lwq.html), it appears
that "Header line length limited only by memory". I would try increasing
the memory limit in the /var/qmail/supervise/smtp/run file (softlimit -m
parameter) and see if that fixes it. Maybe double the value initially.
Thanks for the nice report, and be sure to let us know how you make out.
--
-Eric 'shubes'
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