I’m working on a very odd problem, and I’ve been chasing my tail for days. My question is two-fold, what would be causing it… and, what are some good methods for port specific troubleshooting to overcome similar problems that I may encounter.
I have a remote site (a mobile trailer unit) with a server running a one port TCP service. This unit has a Balance 310 unit in it, with the HQ being the other end of the VPN tunnel.
Everything works fine in both locations. Both routers are routing the traffic between the two subnets correctly. But… As soon as I port forward traffic down from the ISP at the HQ to an IP address that exists on the other end of the tunnel, it fails.
The remote unit server is accessible from either LAN on the service port. So the traffic to the port is making it across the tunnel.
What am I missing here? Surely it’s something small. I’m going to draw up the configuration to better explain the setup, and include some of the subnet/equipment information.