I have two branch office VPN connections, one to Atlanta and one to Italy. We are all on Windows Platforms as well as hosting our own Exchange Servers. I have setup a domain trust with Atlnta and all is fine. Secondary zones in each DNS server, two-way trust .... can send AND recieve mail no problem. My connection to Italy is identical, BUT if I add a zone for their domain in my DNS, I can no longer send mail to them.
You do not have permission to send to this recipient. For assistance, contact your system administrator.
<#masking for security reasons#com #5.7.1 smtp;550 5.7.1 Unable to relay for #email_address#
They are able to add a zone in their DNS for my domain and send mail no problem. Our configurations are identical in DNS and Exchange. What else am I missing?
Just to be clear ... I can send and recieve to Italy no problem if I remove the DNS zone from my server.