Re: 554 SMTP synchronisation error - when users send large numbers of messages

BCC is processed differently in that a message is broken up into many, one for each BCC recipient, so the behavior where BCC doesn't reproduce the problem is expected. Again, I believe the problem is with your ISP's SMTP server, that is I believe it is that server that is issuing the 554, but I wouldn't be able to say for sure without looking at the SMTP protocol logs. And I'm not asking you to post them here, you can look at them yourself to try to figure out what's going on.
--
Ed Crowley MVP
"There are seldom good technological solutions to behavioral problems."
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"Pete Halasovski" <pjh43@xxxxxxxxx> wrote in message news:gsagtr$lh8$1@xxxxxxxxxxxxxxxxxxxxxxx
Hi Ed,

Thanks for the reply. I mean our Exchange server by 'the server' - we have a simple set up - one Exchnage server that functions as mail store & SMTP box and another exchange server that handles webmail.

The other problem with our problem is that the user reported symptom inconsistent. An earlier test I did was to get my user's original message and recipient list and resend it from another account with a please-ignore-this-test preamble - all recipients were BCC'd. We had logging set to it's finest level on our router and I watched our Exchange logs like a hawk. Nothing came back - all messages were delivered, no NDR's, no log entries. nuthin'. One recipient who is a helpful nerd acknowledged reciept and said some people had received previous copies of this message. I examined the mailing list and compared it to the Exchange server's application log of the last failed mailing. The message was sent to 155 recipients. The log shows the "554" errors for mail list recipients in 5 blocks that preserve the entry order in the original list but jumbles it up the groups like so:

10-18
80-99
19-39
100-123
126-133

The lines above are the order of the entries in the mail list given in the order they appear in the error log. If that makes sense.

The Exchange server application log for these entries reported event ID 7004 "This is an SMTP protocol error log for virtual server ID 1, connection #nn. The remote host "xxx.xxx.xxx.xxx", responded to the SMTP command "rcpt" with "554 SMTP synchronisation error ". The full command sent was "RCPT TO: <xxx@xxxxxxx> ". This will probably cause the connection to fail."

At this point my brain starts to bleed...

regards,

Pete

"Ed Crowley [MVP]" <curspice@xxxxxxxxxx> wrote in message news:uJABdCuvJHA.5244@xxxxxxxxxxxxxxxxxxxxxxx
Please explain what you mean by your last paragraph. What server is "the server"?

As to your first problem, if your users are having a problem sending to a large number of external recipients, then I'll wager that your ISP's SMTP server is limiting the number of recipients. You can find out more by enabling SMTP protocol logging, sending a message that fails, and looking at the logs. Dollars to doughnuts that their server bounces the message.

As to the receiving problem, I can't tell you from your diagnostic whether the problem is between your correspondent and your ISP, or between your ISP and your Exchange server.
--
Ed Crowley MVP
"There are seldom good technological solutions to behavioral problems."
.

"Pete Halasovski" <pjh43@xxxxxxxxx> wrote in message news:gs6s16$d34$1@xxxxxxxxxxxxxxxxxxxxxxx
Do you use your ISP's SMTP server as a smart host? If so, I suggest you discuss this problem with them.

Yes they do and I have and they have suggested this is a problme at our end. Before I go and jump up and down at them I want to be sure of my ground. My reading suggests two possible external causes to the one testable symptom (telnet to port 25) that I have experienced:

1) Macaffee Virus scan is blocking port 25. Not any more - I was running virus scan but I deinstalle din favour of Groupshield.
2) Cisco router may be blocking ESMTP through Mailguard. We hav recently introduced a new Cisco firewall but Mailguard is turned off.

Soooo This still leaves me with one symptom:

I can telnet to the server from it's own console (telnet serv.ip.addr.ss 25) but not from another workstation on the same subnet. Our router sees the packets travel from workstation to server but nothing in return. Can you suggest any method for debugging this one?

regards,

Pete






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