I have the following situation.
Two Exchange 2003 Servers in one AD with two subnets (seperate locations) linked by VPN.
Server A: email @[url removed, login to view] and @[url removed, login to view]
Server B: email @[url removed, login to view]
Administrative group with two routing groups, each with a SMTP connector and a Routing Group connector. Each server has two SMTP connectors: port 25 and port 26. Port 26 is used for external e-mail: the cisco router maps port 25 (external) to port 26 internal so that smtp communiction (over port 25) between the two servers is possible.
Everything worked fine until somehow something was changed: internal e-mail between site A and site B isn't possible anymore! (delivery status notfication e-mails). And I have also one user at site B with an additional site A e-mail address which doesn't function anymore.