Mailing List SIMS@mail.stalker.com Message #12619
From: Bill Cole <listbill@scconsult.com>
Subject: Re: can't send e-mail from Mail under Mac OS X
Date: Wed, 5 Mar 2003 00:06:22 -0500
To: SIMS Discussions <SIMS@mail.stalker.com>
At 6:28 PM +0100 3/4/03, Krzysztof Szeloch  imposed structure on a stream of electrons, yielding:
Christian,

I have increased SIMS' SMTP log sensitivity, and tried to send something from Mail through SIMS again.

Here is the the part of the log:


[...]

18:09:34 5 SMTP-720() Stream Created
18:09:34 5 SMTP(720) Resolver Created
18:09:34 4 SMTP Line 720 created for answering
18:09:34 4 SMTP-720() Got connection from [192.168.203.16:49156]
18:09:34 4 SMTP(tcp) Connection accepted from [192.168.203.16:49156], seq=571, 11/12
18:09:34 4 SMTP-720([192.168.203.16]) Sending 220-bulls.com.pl Stalker Internet Mail Server V.1.8b9d14 is ready.\r\n220 ESMTP is spoken here. You are very welcome\r\n
18:09:34 5 SMTP-720([192.168.203.16]) OT 116 of 116 bytes sent, Flags=0
18:09:34 5 SMTP-720([192.168.203.16]) *Status=22
18:09:34 5 SMTP-720([192.168.203.16]) Received 16 bytes
18:09:34 4 SMTP-720([192.168.203.16]) Input Line: HELO eranet.pl\r
18:09:34 5 SMTP-720([192.168.203.16]) *Status=21
18:09:34 4 SMTP-720(eranet.pl) Looking for eranet.pl
18:10:09 3 SMTP-719(eranet.pl) Failed to verify. Real address is [192.168.203.16:49155]
18:10:09 4 SMTP-719(eranet.pl) Sending 250-bulls.com.pl cannot verify eranet.pl\r\n250-HELP\r\n250-ETRN\r\n250 EHLO\r\n
18:10:09 5 SMTP-719(eranet.pl) OT 72 of 72 bytes sent, Flags=0
18:10:09 5 SMTP-719([192.168.203.16]) *Status=22
18:10:09 3 SMTP-719([192.168.203.16]) Abort Received, reason=54
18:10:09 4 SMTP-719([192.168.203.16]) Nothing read - stream broken
18:10:10 3 SMTP-719([192.168.203.16]) Reading Failed. Error Code=-25010. Read:

[...]

Does it say anything to you?


Yes.

For some reason, the client is announcing itself as 'eranet.pl' and for some equally unknown reason, SIMS is taking a fairly long time (35 seconds) to check that name for resolution back to the connecting address and coming up without anything. It seems that the client is unwilling to wait that long and is just dropping the connection.

There are actually 3 problems here:

1. The client is claiming to be 'eranet.pl' which it clearly is not. This is either a client bug or a problem with the configuration of the machine it is running on. The proper HELO argument is a fully qualified domain name which does in fact identify the machine sending the HELO command.

2. SIMS is failing to resolve eranet.pl and is taking a long time to fail. I can resolve eranet.pl in under a second and I'm on a different continent. This hints at SIMS having very bad DNS at its disposal.

3. The client is giving up on SIMS in less than 35 secconds. This is simply too short a timeout for an SMTP client. SMTP servers may do name resolutions at many points in a transaction, and name resolutions by their nature can stall for fairly long times. Even 60 seconds might be a little too aggressive a timeout, but 35 seconds is silly.
--
Bill Cole                                  bill@scconsult.com

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