Hi I hope you can help.
I have set a domain trust between my company and a newly acquired company. I will call them DomainA and DomainB.
DomainA is 2003 function level with 2008R2 DCs and Exchange 2010 2 x HTS/CAS and 2 x Mailbox DAGs
DomainB is 2000 function level with a 1 2000 DC and 1 2003 DC with an all in one Exchange 2007 running on 2003
I set up DNS Zones for the corresponding domains (The 2000 was manual with no AD replication)
I set up External trust 2 way with 2000 compatibility
The trust works fine and both domains and objects can be seen and used bothways
However, once the domain was in place mail could not be sent between domain. Mail to any extrenal address is fine. But internal email gets an "unable to relay for sender@domain.com.I am assuming that as the mail is getting routed across the VPN it sees it as an unauthorized relay?
Do I just need to add send connectors to allow the IP addresses of the Exchange servers in the other Domains, should I route the mail externally or should I set each up as a trusted domain on the exchange servers.
Thanks in advance
Steve