OK all you Exchange experts, can you help me?
I have 2 identical HP Netservers running NT4.0SP6a Server with Exchange 5.5 SP4. One has been running happily for over 12 months and has 250 users (serverA), the other I set-up a few days ago and has 7 users (serverB). They are behind a FreeBSD firewall with Squid proxy and are on the same subnet (192.168.4.xxx) but different NT domains. 2 way trusts have been set-up and tested. They are 2 completely different Internet domains.
Both can send and receive e-mail to the outside world without trouble. ServerB can send e-mail to serverA without trouble. ServerA cannot send to serverB. i.e. mail to recipient@domainB sits in the queue of the exchange server of domainA. The messages sit in the queue with a host network unreachable error. Checking the event log indicates the connection was refused.
I?ve temporarily got around the problem by setting up all serverB recipients in serverA and forwarding them to a forwarding service, which sends themback to serverB. i.e. anyone on serverA wanting to send an e-mail to serverB would send it to recipient1@domainA. This is then forwarded to a different e-mail address (recipient1@externaldomain), which is then forwarded to recipient1@domainB. This works, as it gets it through the firewall to an external site before it comes back. The proxy/firewall isn?t causing the problem.
Any ideas?