Transmission on FreeNAS - problem with listening port

[uncle_jim 0]

Hello all. I'm trying to run Transmission on FreeNAS 9.2.1.5, and can't seem to get the listening port working correctly. I have forwarded the port as per the FAQ (TCP/UDP, no DDNS) and the TCP test shows that the computer is reachable on that port, but in the Transmission settings the port reads as closed.

 

I am running Transmission in a single plugin jail alongside SABnzbd, SickBeard and CouchPotato, all of which are configured with forwarded ports with DDNS for external access, and which work perfectly fine. I have OpenVPN running behind an ipfw firewall, which is allowing all other traffic through.

 

Has anyone else encountered this problem before and have a solution? It's the only part I don't have working perfectly and I'm tearing my hair out over it.

 

Thanks in advance.