troubleshooting Question

Creating a working relay between two Exchange Servers / SMTP problems

Avatar of Robox1
Robox1Flag for United Kingdom of Great Britain and Northern Ireland asked on
Email ProtocolsExchange
22 Comments1 Solution928 ViewsLast Modified:
Hi,

We have recently taken over a support contract for a company that is running two Exchange servers, one is running Exchange 6.5 and the other is running Exchange 2007. Their are 5 domains in use on both Servers, one domain is solely used on the Exchange 6.5 and 3 are solely used on the Exchange 2007. The 5th domain has some mailboxes set up on Exchange 6.5 and others set up on Exchange 2007. The MX record for this domain points to the Exchange 6.5 machine and I assume that any mailboxes encountered that reside on the Exchange 2007 machine are relayed to the Exchange 2007 machine. This was working, until the public IP address was changed on both PC's. Emails are still being received and relayed to the Exchange 2007 machine, but emails sent from the domain in sole use on the Exchange 6.5 machine are bounced back to the sender with the error "#5.7.1 smtp;550 5.7.1 Unable to relay for <email address sent to>". If I change the SMTP connector on the Exchange 6.5 machine to forward through the ISP SMTP server (smtp.eclipse.co.uk) then the emails send fine, but the relay between the Exchange 6.5 machine and Exchange 2007 machine stops working.

Can anyone offer any clues as to why this is happening?
ASKER CERTIFIED SOLUTION
MegaNuk3

Our community of experts have been thoroughly vetted for their expertise and industry experience.

Join our community to see this answer!
Unlock 1 Answer and 22 Comments.
Start Free Trial
Learn from the best

Network and collaborate with thousands of CTOs, CISOs, and IT Pros rooting for you and your success.

Andrew Hancock - VMware vExpert
See if this solution works for you by signing up for a 7 day free trial.
Unlock 1 Answer and 22 Comments.
Try for 7 days

”The time we save is the biggest benefit of E-E to our team. What could take multiple guys 2 hours or more each to find is accessed in around 15 minutes on Experts Exchange.

-Mike Kapnisakis, Warner Bros