I have ISA Server 2006 installed and I have a problem connecting two subnets through port 443. Both networks are defined as ranges in the Internal Network and the following access rule is defined to allow traffic:
Protocols: HTTPS (no filters, HTTP (no filters), 8080 From: local host, Internal To: All networks (And local host), External, Internal Users: All users
The problem is one subnet (138.0.1.x) cannot access by telnet using port 443 to the other subnet (172.16.146.x) trhough ISA Server, but I can access from the subnet 172.16.146.x to 138.0.1.x. Also, ISA can access both 172.16.146.x and 138.0.1.x using this port. I have checked logs and the connection is logged by 0x0 ERROR_SUCCESS message, and 1 later it appears 0xc0040038 FWX_E_TCP_NO_SERVER_REPLY message.
I have tried a lot of configurations but I haven't get it. I think it's possible ISA Server is blocking this port From Internal to Internal for some reason that I don't know, because I can access doing 443 telnet to any server of External network.
I have resolved the problem. It seems ISA Server doesn't work properly if two subnets are defined in the same network and there are rules created between them. I have created a new computer object with containing the IP of one of the machines and I added to the FROM entry of the rule, and now it's working. I don't understand why it didn't work because that IP is included in the Internal network, but I don't know why now it's working in this way.
I hope this information help people with the same problem.