I'm trying to set up a firewall so that we can allow our SIP server to take incoming phone calls. I've been told to open up ports 5060 - 5070 UDP, and ports 8766 - 35000 TCP / UDP to the back-end server. The thing is, I just can't get it to work.
I've got a ZyXEL P-660H firewall providing simple no-NAT connectivity from an ADSL line, with no firewalling or anything. It simply routes traffic from a phone wire to an ethernet cable as far as I'm concerned. Sat behind that, I've got a Draytek Vigor 2910VG firewall, which provides VoIP facilities. I don't think I want to use those as such, as I've got a full-blown SIP server in the background, but I'm not sure where to start. Does anybody have any experience of these firewalls? Any experts out there who can help?