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Slow outgoing mail

I have Exchange 2k3 running on Win 2k server. Outbound mail is very slow. Incomming mail is almost instant. When I test from my hotmail account it seems that the second I click send the mail arrives. But sending from my Exchange server to my hotmail account it takes 10-15 minutes for the mail to arrive. We have a Symantec firewall which acts as our DNS. 2 weeks ago the old firewall was replaced with a new one and the config copied over. But it seems that's when the trouble started. Any help would be appreciated. If you need any more information let me know. Thank you all.

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Sembee

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ewest111

ASKER

We have internal DNS servers but they forward to the Symantec Security Gateway. That device then talks to the root DNS servers and does the resolution. I'm told that the setup is correct. Confused me as well. I've only been with this comapny a short time and am still trying to figure this mess out. Yes the messages are in the queues. I send mail directly, not with a smart host. What might I be looking for in the event log. I've turned up logging periodically the last couple of days to try and see what errors are occuring. Any suggestions on which logging items to turn up and what to look for?

Sembee

Using the root DNS servers I have found can be slow. For the best performance of DNS I will configure forwarders on the DNS server applet of the domain controllers and point them at the ISPs DNS servers. I have done that with all of my deployments and haven't seen any DNS errors since.

The messages may be stuck for other reasons. If your email goes through the Symantec device then it could be that the Symantec device is configured incorrectly, perhaps it is interfering with the SMTP traffic flow.

Simon.

ewest111

ASKER

A follow up on this question. I also see that I have a huge amount of mail in my outbound SMTP queue. What could be causing this bottleneck?

Sembee

Many many reasons for that. Without further information it is impossible to tell.

You could be under attack, NDR, directory harvest etc. In that case you would need to clean up.

Without further diagnosis of what the messages are then it is impossible to say much more.

Simon.

ewest111

ASKER

Any direction that you can point me in would be helpful.

Sembee

You have to look at the queues to see what sort of messages they are. It is your server, you should know what messages are normal. If the server is under attack then you will see lots of odd email domains in the queues.

Simon.

ewest111

ASKER

All the outgoing mail looks fairly normal. Lot's of AOL but that's normal for this place.

Sembee

If you are having problems with AOL email, then an SMTP Connector to route email for AOL via your ISPs SMTP server will fix that problem.
http://www.amset.info/exchange/smtp-connector.asp

You said in an earlier post that you had lots of messages in the queues. With the exception of AOL messages, is that still the case?

If you look at message tracking, can you see a delay in the message flow through the system?

Simon.

ewest111

ASKER

It turned out to be a DNS configuration issue after all. I'm accepting the first answer based on that fact as I started diving deeper into it from that point. Thanks.