Re: Reading Exchange 2003 SMTP Logs / Expected emails don't always arrive

Paul,

Thanks for your reply.

1) As far as I'm aware, no, the sender does not receive an NDR but I am
aware that there are soem emails that are being sent to our ISP's replay
servers which appear to be unable to forward them to us although I can see
communication between the servers. The ISP's replay servers never send the
DATA or BDAT command and the just quit after a short while.

2) I would say that the vast majority of emails get to us. To the best of my
knowledge were are experiencing the issue from only 2 external domains (one
is our ISP or more precisely their relay servers, and the other is a parent
company).

3) No. The message doesn't appear in the tracking logs. It's as if it's
never actually sent. Those that do appear in the tracking logs do arrive in
the users mailbox.

4) It does appear that the issue is occuring only with emails which have
attachments, but I have checked the 'Message Delivery Option' defaults and
both incoming and outgoing size restrictions are set at 15360KB. I'm not
aware of issues with emails which have no attachments (I have sent myself
countless test emails from private webmail accounts) and they all seem to
get through.

For your info, I have now opened a case with Microsoft. I'll post back when
I have some useful feedback/info but in the meantime if you have any
suggestions etc, they would be gratefully received.

Thanks again for taking the time to read, reply and help.
Sergio

"Paul Ford (Edge IT Ltd)" <paulford@xxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:%231bTuRRYHHA.4440@xxxxxxxxxxxxxxxxxxxxxxx
Sergio,

A few questions to see if we can work out the cause of the issue.

Does the sender of the message ever recieve an NDR ?
Do any other senders from other companies report any issues sending email
with attachments ?
Does the message appear in the message tracking logs your Exchange server
?
Does it matter what size the attachments are i.e. do smaller attachements
get through ?
Do emails with no attachments get through from the sender experiencing
issues ?

Regards

Paul Ford


"Sergio" <myname@xxxxxxxxxxxx> wrote in message
news:e5zVthMXHHA.4880@xxxxxxxxxxxxxxxxxxxxxxx
Hi,

We have been experiencing an issue now for a week or so and feel as
though I have exhausted every avenue in trying to find out why we are
having this issue. Essentially some emails (with attachment) aren't
always received by our users. The senders of the emails are, to the best
of my knowledge, always the same users. From what I can make out the
senders IT infrastructure has multiple Exchange servers
(maila.domain.net, mailb.domain.net, mailc.domain.net etc).

I have checked that no emails are getting blocked by the RBL we use and
have included the senders domain in a white list. I have checked that the
emails are not getting caught by our antivirus software. The email that
doesn't appear to arrive typically contains an attachment (approx 1 MB in
size) and is sent to many people (maybe 30 or 40). I can confirm that
there isn't a restriction that would block the email due to the number of
intended recipients (I have left the default setting of 5000 in Exchange)
and likewise for inbound and outbound mail size (currently set to 15 MB).
There are no individula limits set.

I have setup SMTP logging and would like some assistance in reading the
following extract (I have changed both the senders IP address and domain
name for obvious reasons).

My understanding is that, taking the extract below:
1) server 'maild.domainn.net' with IP address 1.2.3.4 has established
comunicaton with our server 'SERVER1' with IP address 192.168.30.3
sucessfully (EHLO 250).
2) It then goes on to declare the senders email address (MAIL 250)
successfully.
3) It declares the email address of the recipients successfully (RCPT
250), and in this case there are 4 recipients.
4) There does *not* appear to be the DATA or BDAT declaration which would
tell our server to expect data (the email) to follow, it just quits
successfully (QUIT 240).

Is this normal? Why is there no DATA or BDAT?

2007-03-02 11:11:17 1.2.3.4 maild.domain.net SMTPSVC1 SERVER1
192.168.30.3 0 EHLO 250 311 27 0 SMTP -
2007-03-02 11:11:17 1.2.3.4 maild.domain.net SMTPSVC1 SERVER1
192.168.30.3 0 MAIL 250 54 41 15 SMTP -
2007-03-02 11:11:17 1.2.3.4 maild.domain.net SMTPSVC1 SERVER1
192.168.30.3 0 RCPT 250 42 39 0 SMTP -
2007-03-02 11:11:17 1.2.3.4 maild.domain.net SMTPSVC1 SERVER1
192.168.30.3 0 RCPT 250 44 41 0 SMTP -
2007-03-02 11:11:17 1.2.3.4 maild.domain.net SMTPSVC1 SERVER1
192.168.30.3 0 RCPT 250 43 40 0 SMTP -
2007-03-02 11:11:17 1.2.3.4 maild.domain.net SMTPSVC1 SERVER1
192.168.30.3 0 RCPT 250 42 39 0 SMTP -
2007-03-02 11:12:59 1.2.3.4 maild.domain.net SMTPSVC1 SERVER1
192.168.30.3 0 QUIT 240 42 39 101406 SMTP -

In both the extracts below for SMTP communications from
'maill.domian.net' and 'mailm.domain.net' the process follows the steps
above but does contain the BDAT command.

2007-03-02 11:30:16 10.11.12.13 maill.domain.net SMTPSVC1 SERVER1
192.168.30.3 0 EHLO 250 312 27 0 SMTP -
2007-03-02 11:30:16 10.11.12.13 maill.domain.net SMTPSVC1 SERVER1
192.168.30.3 0 MAIL 250 56 43 0 SMTP -
2007-03-02 11:30:16 10.11.12.13 maill.domain.net SMTPSVC1 SERVER1
192.168.30.3 0 RCPT 250 44 41 0 SMTP -
2007-03-02 11:30:16 10.11.12.13 maill.domain.net SMTPSVC1 SERVER1
192.168.30.3 0 BDAT 250 118 20136 203 SMTP -
2007-03-02 11:30:16 10.11.12.13 maill.domain.net SMTPSVC1 SERVER1
192.168.30.3 0 QUIT 240 67 4 0 SMTP -

2007-03-02 11:34:21 100.101.102.103 mailm.domain.net SMTPSVC1 SERVER1
192.168.30.3 0 EHLO 250 312 27 0 SMTP -
2007-03-02 11:34:21 100.101.102.103 mailm.domain.net SMTPSVC1 SERVER1
192.168.30.3 0 MAIL 250 56 43 0 SMTP -
2007-03-02 11:34:21 100.101.102.103 mailm.domain.net SMTPSVC1 SERVER1
192.168.30.3 0 RCPT 250 44 41 0 SMTP -
2007-03-02 11:34:21 100.101.102.103 mailm.domain.net SMTPSVC1 SERVER1
192.168.30.3 0 BDAT 250 118 35705 313 SMTP -
2007-03-02 11:34:21 100.101.102.103 mailm.domain.net SMTPSVC1 SERVER1
192.168.30.3 0 QUIT 240 67 4 0 SMTP -

I have run pretty much every test I can think of on our servers and can
find nothing wrong but would grately appreciate any advice and/or
assistance even though I am beginning to think the problem may not be at
our end or may have something to do with the SDSL line we use for
Internet connectivity. I have also run Microsofts MS Exchange
Troubleshooting Assistant and that too came back clean.

I should mention that we use MS Exchange 2003 with SP1 which runs on MS
Windows 2003 with SP1 also.

Thanks in advance for any thoughts, comments and assiastance.
Sergio





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