Exchange 7002 7004 errors

[Jimmy G]

Hey guys, I need some urgent help from you all. We are running SBS 2003 Premium machine with Service Pack 1 and Exchange SP1 installed. In this scenario Exchange sends mail via DNS, and receives mail using an SMTP de-queuing facility from my ISP‘s global mailbox. All this was working fine until 3 days ago but since then we are not able to either receive or send mails any more.

We checked the event viewer and it shows many entries for 7002 and 7004 errors. Clicking on 7004 says:

"This is an SMTP protocol error log for virtual server ID 1, connection #6. The remote host "xxx.214.129.136", responded to the SMTP command "xexch50" with "504 Need to authenticate first ". The full command sent was "XEXCH50 1028 2 ". This will probably cause the connection to fail."

And 7002 says:
This is an SMTP protocol warning log for virtual server ID 1, connection #1256. The remote host "xxx.82.248.45", responded to the SMTP command "rcpt" with "421 Service Temporarily Unavailable ". The full command sent was "RCPT TO:<andkin@s2f.com.au> ". This may cause the connection to fail.

Any help will be appreciated.

[Patton]

First of all I would like to know whether your Exchange Server sending NDR's to the world? Its usually NDR's to spam which came in and then "acts up" when trying to send NDR's. If you are using this then you must turn off NDR temporarily, clean up your outbound queue and start the service again. See if it fixes the problem.

[Jacob.M]

I've seen this before see MSEX2K3DB for the solution that worked for me.

[Jimmy G]

Thank you all for all your responses. I managed to fix the problem now. Starting to look like some issue with SMTP headers, because telnettting to two domains worked fine... Logged support call to ISP, another 30 mins on phone (your call is important to us...BAH!), left phone no. - Never heard a peep.