From: Bill Sadvary (sadvary@dickinson.edu)
Date: Wed Jul 30 2003 - 08:59:57 EDT
Tru64 Managers,
Sorry for the late summary but a fix was never really found, just a
workaround. Sigh. The original post is below.
Basic scenario:
We could send mail to their Domino Notes server but their mail to us would
timeout and go undelivered. However, they could send us mail from another
host on their same network as the Notes server. So it was only between our
two Tru64 servers and their Domino Notes server.
Summary:
To make a LONG STORY short... For some unknown reason, the 220 packet
that our mailserver (AlphaServer Tru64 v4.0g) was sending to their Domino
Notes mail server never made it through our Packetshapper (bandwidth
manager). But 99.999999% of all other Internet mail was coming/going
through just fine.
Unfortunately, things got a little sticky between us and them, finger
pointing, that kinda bullshit and a real solution was never discovered.
We saw some strange DNS replies from their DNS but they were not willing
to make any of the harmless 'test' DNS changes that we suggested. Also, I
found a Domino Notes TechNote that suggested to increase the Notes
SMTPTimeoutMultiplier value but, again, they were not willing to give it a
try. Why? I dunno. Again, it seemed harmless to me.
http://www-1.ibm.com/support/docview.wss?rs=0&uid=swg21099762
Back to the Packetshapper. We created a special high priority traffic
class for their entire network. So basically, all traffic to/from them to
us was high priority. It didn't make a bit of difference. Only when we
totally turned off our Packetshapper would the 220 packet pass through.
Obviously, turning off our Packetshapper was not going to be the ultimate
solution to the problem.
Workaround:
They ended up routing their mail destined for us through another mail
server on their network. Well, that's how it appears to me. They totally
ceased all communications with us. A shame, I know.
If anyone does solve this mystery, PLEASE let me know. ...just outta
curiosity sakes!
-Bill Sadvary
SysAdmin
Carlisle, PA
Original Post
-------------
We're having problems receiving mail from just a handful of sites on the
Internet. It's a really strange problem and one that maybe you can lend
some assistance.
I'll use "XXX.COM" as the remote site name in my examples with a
bogus 123.123.123.123 as the IP address.
I'm seeing this exact same problem and two different Tru64 v4.0g (fully
patched, including all security patches) Alphaservers running Sendmail
v8.8.8.
Ok, Here goes...
I can send mail to XXX.COM with no problem. But, when they send a message
to us, it times out and goes undelivered.
Here's the mail.log errors on our end..
May 2 07:59:18 alpha sendmail[31795]: NOQUEUE: Null connection from
XXX.COM [123.123.123.123]
May 2 07:59:35 alpha sendmail[5014]: NOQUEUE: timeout waiting for input
from XXX.COM [123.123.123.123]
Upon talking with the XXX.COM NetMgr, he is seeing the TCP/IP 3-way
handshake and then nothing else happens. He can telnet to port 25 of our
mail server but gets no response when he issues the "helo" command. Very
strange.
He can ftp from XXX.COM to our mail server without a problem. We would
have tried a regular, interactive telnet session but his firewall doesn't
permit it.
I did a test from my workstation by telneting to our mail server's port 25
and then I just let the connection die on it's own and the mail.log showed
the exact same error message.
We're not blocking any XXX.COM mail via sendmail or the firewall.
Any ideas why the connection gets established and then just dies? It
doesn't appear to be a network problem since I cam email them and they can
connect via ftp without a problem. It doesn't seem to be a DNS problem
since the mail server is able to do the lookups for their site. It's seems
like a sendmail issue on our end..
Thanks,
-Bill
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