I just got mine as a replacement for a dying ancient unit from Lingo but it seems to be unlocked so I can snoop around .
My WAN side Web Server is set to port 8008. But, it appears it limits connections to only certain IPs, in Lingo's case: iprimus.net, primusvoip.com, primustel.com . Or it may only be limited for Voice setup and the router setup might not be limited, I'm not sure how to interprete the settings I see.