Full Cone Routing on Linux

Hi, Anyone knows how to build full-cone router on Linux, prefferably with Shorewall? For SIP VoIP clients I am need full-cone routing behind NAT. Thanks in advance for any suggestion(s). ********************************************* * Best Regards --- Andrei Verovski * * Personal Home Page * http://snow.prohosting.com/guru4mac/ * Mac, Linux, DTP, Development, IT WEB Site *********************************************