Help! a real puzzler...

[albracco]

Here's the scenario:

Company A has a Windows 2003 domain with their own Exchange 2003 server. email domain is companya.com

Company B is a subsidiary of a much larger company. They have their own windows 2000 domain server and got their email through the exchangeb server of their parent company. email domain is companyb.com

Company A aquires Company B, but wants to conmtinue letting run as a separate entity. Company B keeps their domain server, but now gets their email through Comnpany A's Exchange server (they were setup as a separate OU in AD). MX record was changed to point to company A's Exchange server.

This all occurred several weeks ago, and all has been working fine - ALMOST!
It seems that randomly, some email messages (new and replies) meant for a companyb user is bounced back to the sender with a message that the recipient does not exist (but it does). The interesting part is that just below that bounceback message is referenced company B's old email servername. It's as if some random messages are getting routed to company B's old server. The MX record is correct and it's been several weeks, so I would expect all DNS servers to be up-tp-date.

Running a DNS report at dnsstuff.com does not show any problems (just a warning about not having an SPF record).

Any suggestions on how to troubleshoot this?
Post #: 1

 

[ShackDaddy]

You know, I think you're still dealing with cached records out there. This can't be troubleshot from your end, only from the end of the servers who are having the problem.

If I were you, I'd send email out to the admins of some of those domains and let them know that while you've had everything squared away on your end for a while, for some reason their servers are still sending to an old MX record. They may need to examine how they've configured caching (some admins do some crazy things to "reduce traffic"), or something else.

ShackDaddy
Shackelford Consulting