Typically the port you need for joint ops would just be 32768 udp

as i said this is likely the same with dfx.

the port you need to check should be in your game.cfg file, the is an example of this by dd-huntor here:

http://www.novaworld2.com/index.php?do=/public/forums/display_topic/id_5886/

your friend likely changed his game.cfg the other thing is (some routers dont support it and some you have to turn it on and some will do it by default) turn on something called nat refection... without it you can host but you wont be able to join your own server from a second copy in the same network... but if you only have one copy and intend do host and play, its not something you need to worry about.

The router you have sadly being the hp version wont take a ddwrt or openwrt flash where as most of the normal 841 routers will, but the spec looks good and those antennas are huuuuge :-) it must get some good range.

so service door : 32768

internal door : 32768

ip : the static ip of your server/computer

Type: UDP

oh and on the upnp option, its good security practice to turn this option off completely.

on your pc make sure you have set the ip address using a static method and not by dhcp, as the moment dhcp gives you a new ip your going to find the port forward is broken and will need changing to the new ip.