SMTP messages not leaving server

[NicktheNewbie]

I'm getting the following error, and many/most outbound messages don't seem to be leaving the server.

This is an automatically generated Delivery Status Notification.
THIS IS A WARNING MESSAGE ONLY.
YOU DO NOT NEED TO RESEND YOUR MESSAGE.
Delivery to the following recipients has been delayed.
test@hotmail.com

What could be causing this?

 

[NicktheNewbie]

I forgot to add:
outbound messages are the only problem.

We get inbound just fine, and users can send to other users (on this same exchange server) without issue.

 

[fraziergs]

if it is all of your messages, have you changed any of your network settings lately, DNS, firewall, etc? Either of these could be the source of your problem.

 

[NicktheNewbie]

No DNS changes, or anything else really.

Anybody know of a general troubleshooting faq I might use?

 

[PGTurner]

Is it every outbound message or just some? Are you sending directly to destination or are you using a remote mail handler?

If every, then there could be something amiss with Exchange/SMTP connector - but my problems have always been with certain destinations, even certain messages.

If that is the case you need to BE an SMTP connector and see what happens. Pick a failed message from the queue -status will be retry.

Find the destination e.g. hotmail.com. use nslookup,
set type=MX
hotmail.com.
should return the mail exchanger for that domain

hotmail.com MX preference = 5, mail exchanger = mx1.hotmail.com

no MX record then problem is with destination address or your DNS. Try internet DNS lookup tools to verify one or the other

Try ping of server from MX record e.g. mx1.hotmail.com - doesn't prove anything if it doesn't ping but if it does you know it exists. yahoo's mail servers ping, hotmail's don't.

Try telnet mx1.hotmail.com 25 - if you get a helo of sorts then at least you have connection. quit closes the connection. No response means you are unable to contact destination mail server.

That could be as simple as destination server being down - hotmail - not likely. Perhaps overloaded.

I recently have been having trouble with one destination. I can telnet to it from my home office ( one network ) but not from network Exchange is on. Telnet just fails. I claim the destination has me blocked - they deny it but ??

Anyway, mail destinations may use a variety of tricks to keep spam out - your server may have been black listed due to open relay or other abuse - there are web sites that will report your blacklist status.

Check that your reverse DNS operates - there are web sites for that as well - some mail handlers won't accept a connection unless the IP you are coming from has a valid reverse DNS.

If you got a helo from the mail server, then the problem can be with the message itself. I have had one message jam up a queue with something in the message - never did figure out what it was - I could freeze that message everything else would then clear out and continue to operate - unfreeze, it would retry that message, fail and not attempt any others in the queue.

I located that by cranking up the detail on the logging - I could see that it connected, started the send, then the server hung up. When that message was frozen, others just cruised on through.

If you got a helo there can be problems with the destination mailbox - usually it doesn't exist - but that doesn't generate a delivery delay - it just fails.

I have also recently seen problems with secretary using send-as for administrator being rejected by overly-aggressive spam gizmos.

If you are still battling, this should give you some possibilities but there are many ways for things to fail.

I have been doing the same thing a lot recently - each seems to have a different story - but all my users see is "Our mail isn't going out - what have you done to break it?" In my case, it isn't all mail but there have been enough for them to think there is some single cause - so far it hasn't been.

 

[Marcs41]

See:

http://support.microsoft.com/default.aspx?scid=kb;en-us;329636&Product=exch2k

Marc
[sub]If 'something' 'somewhere' gives 'some' error, expect random guesses or no replies at all. Please specify details.
Free Tip: The F1 Key does NOT destroy your PC![/sub]
How Do I Get Great Answers To my Tek-Tips Questions? See faq219-2884