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Message stuck in SMTP queue

Mail stuck in Exchange 2000 SMTP queue.  No changes have occured.
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Hi rileyadm,
> No changes have occured.
That's not very likely - for a start, it used to work and now it doesn't.  I consider that a change :-)

How is your Exchange server configured to send these emails?  Does it send everything through a smarthost, or do the delivery directly?
How is the server connected to the Internet?  It's worth checking that the server can still connect out on the SMTP port - something could have happened to your firewall/gateway, or your ISP might have changed it's policy on allowing port 25 through.

Many ISP's now block port 25 to anywhere other than their own email server.

To test this, follow the instructions at http://support.microsoft.com/default.aspx?kbid=153119 and try to connect to your ISP's mail server.
If that works, try connecting to a mail server for an address that you've got stuck in your queue (assuming direct delivery)

Is this happening to all emails, or just some?  When did the problem start?
rileyadmAuthor Commented:
Our Exchange server sends mail to a backend SMTP server.  We are connected via a T1.  I cannot get out on port 25 on that server but I can on my desktop to other mail servers.

We do not use an ISP for mail. We can receive inbound mail but can not send out mail.  This problem started last night around 8:30 p.m.  Let me know if you need additional information.

Can I just clarify my understanding here?

Connect using telnet test from Exchange to backend SMTP doesn't work
Connect using telnet test from other PCs on same LAN as Exchange to backend SMTP does work
Connect using telnet test from Exchange to other SMTP servers works
Connect using telnet test from other PCs on same LAN as Exchange to other SMTP servers works

I think I might have misunderstood part of this - but it's important that we're clear about exactly what does/doesn't work.

If the above is true, it could be:
A problem with DNS resolution on the Exchange server (or something dodgy in the hosts file)
Something on the Exchange server is firewalling/blocking the connection
Something on the backend SMTP server is refusing the connection.

Also - when you do the telnet tests, can you please tell me exactly what happens?  Do you just get a timeout, or some sort of error message?

rileyadmAuthor Commented:
Thanks for all the troubleshooting help.  I discovered it was a hardware problem.  I faulty switch.  Once I took the switch out of the loop, my problem was resolve.  Does that make sense or just intermitted?

Thanks, rileyadm
That makes perfect sense - especially if the switch has layer 3 functions.
Glad that it's sorted :-)

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