Problem forwarding admin port if not default port of 943

[stephen_liu]

Hello, I have an OpenVPN Access Server behind a firewall/router (Verizon FIOS MR424). I have the admin and client interface ports both set to the shared default of TCP port 943. When I configure the airport extreme to forward port 943 to the OpenVPN AS host, both the admin and client UI interfaces work fine when accessed externally. However, if I try to use a different port, say 8800 and set up the router to forward that to port 943 on my OpenVPN AS host, the admin interface works fine externally, but the client one doesn't (it asks for the certificate exception approval, but then nothing shows up).

Explicitly setting the admin and client port to 8800 in the "Server Network Settings" page works fine though.

Why doesn't forwarding the port work? Is this a problem with my router not forwarding properly or is OpenVPN AS doing something that I'm not aware of?

Thanks.