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Microsoft Exchange not sending mail....

Out going mail has stopped working - the mesages are not leaving the exchange servers.

We have 3 exchange servers all doing the same thing all of a sudden

The message just sit in the queue with one of the following error messags:-

An SMTP protocol error occurred
The connection was dropped by the remote host
The connection was dropped due to an SMTP event sink

If we send to hotmail we get #NDR 5.5.0

Our mailserver is mail.wisemanlee.co.uk 77.73.11.54

The SMTP Diagnostics at MXtoolbox all show ok

No error's in Event log

I can connect to the server via port 25 and send myself a test email using the EHLO commands etc...

I can browse internet from all three server

Rebooted the computers

Stop and start the MTA service and the SMTP service

Stumped now...

Please help 500 points...
0
ise438
Asked:
ise438
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1 Solution
 
fgrushevskyCommented:
it could be a DNS issue on your servers
please take a look here
http://www.experts-exchange.com/Networking/Email_Groupware/Exchange_Server/Q_21110083.html
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MesthaCommented:
The only thing I can see wrong is that you have said your mail server is mail.wisemanlee.co.uk but your reverse DNS is mail.wiseman.co.uk.

However, you do have a Cisco PIX. That can cause problems with email delivery. Turn off fixup SMTP in the PIX configuration and see if that improves things.

-M
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ise438Author Commented:
Morning,

I fixed this by routing outgoing email's via the Spam filter - using it as a Smart Host.

Still none the still not sure why it suddenly stop ?

What does fixup SMTP do ?

Ian
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fgrushevskyCommented:
The Cisco PIX firewall device uses an SMTP protocol filtering feature that is named Mailguard. When the Mailguard feature is turned on, it blocks all Extended Simple Mail Transfer Protocol (ESMTP) commands. Mailguard allows only seven basic Simple Mail Transfer Protocol (SMTP) commands to pass

http://support.microsoft.com/kb/295725
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ise438Author Commented:
Ta - The pix config hasn't changed...
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MesthaCommented:
The fact that you haven't changed the PIX configuration doesn't mean a thing. Previous behaviour is not an indication that either it was correct, or that it will continue to work correctly. Fixup SMTP causes problems, it is well known, so turn it off. While it is enabled looking at anything else is pointless.

-M
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ise438Author Commented:
Ok point taken - How do I turn it off what are the commands to enter into the Pix ?

It has the command fixup protocol smtp 25 - listed in the running config...
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MesthaCommented:
The KB article above explains what you need to do.

-M
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ise438Author Commented:
Looked at the KB

When you try to send or receive messages behind a Cisco PIX firewall, you experience one or more of the following issues:
A user receives an exact copy of the same inbound message over and over. Each new duplicate message is received at a consistent interval. This continues for several hours and then stops suddenly.
THE ABOVE IS NOT HAPPENING

If there is a Cisco PIX firewall device between the routing groups, you experience the following issues:
The X-LINK2STATE verb is not passed. Additionally, you have link state routing issues between routing groups. NOPE THE PiX IS NOT IN BETWEEN ROUTING GROUPS


There are authentication problems between servers because of a routing group connector. - WE ONLY HAVE ONE ROUTING GROUP

You cannot receive Internet-based e-mail messages. - WE ARE RECEIVE BUT IT WON'T SEND UNLESS IT GOES VIA THE SMART HOST (OUR SPAM FILTER)

When you use Microsoft Outlook or Microsoft Outlook Express to send e-mail messages, you receive the 0x800CCC79 error message. NOPE
The Post Office Protocol version 3 (POP3) protocol cannot be authenticated. Additionally, you receive the following error message:
550 5.7.1 relaying denied from local server NOT USINF POP3

You cannot send messages that have attachments. Or, the attachments are missing or garbled.
When you send messages that contain binary MIME (8bitmime) parts, you receive the following error message in a non-delivery report (NDR) message:MAKE NO DIFFERENCE IF IT HAS AN ATTACHEMNT OR NOT...

ANY OTHER IDEA'S
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MesthaCommented:
While that article states what Microsoft have seen, and you are not seeing the same thing, that doesn't mean you shouldn't make the change.

All the time that you have your PIX with that setting enabled, you will not know if it is the source of the problem.

Turn it off. It is known to cause to problems.

If you refuse to turn it off, then I don't think anyone is going to be prepared to assist, certainly I will unsubscribe from the question because until it is disabled I consider that to be the source of the issue.
I suspect that if you were to call Microsoft they would tell you to do the same thing.

-M
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ise438Author Commented:
We all due respect I can't recall saying I refused to turn it off and I very much apprieate would like your help and EE in general.

I have not turn it off - simply because I don't know how ?

Can you tell me what commands to enter into the PiX ? - It's a faily old 506

Ian
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MesthaCommented:
As I wrote earlier, the article linked to above http://support.microsoft.com/kb/295725 tells you how to turn it off.

-M
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snyderkvCommented:
common man, no fixup protocol smtp 25, you can ask your network guys they should already know this or be able to read the article as it is in plain english.

maybe your firewall requires something different, but shouldn't be to hard to work out.

Copied this from a simple search in google

enable
(password)
conf t
no fixup protocol smtp 25
(ctrl+z)
wr me
exit
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