HI. need help. I put a pbx asterisk (astlinux) plugged to tomato router. but it seems that firewall is blocking incoming calls. when external phone calls get into the pbx. the get busy signal. even when te asterisk register the caller id of the caller. but when I dial with a sip line in my pap2 the call pass thru fine. and no busy signal is ear but the pap2 and asterisk are both plugged into tomato router. so if the calls from inside the network pass trhu. but that ouside not. maybe is the firewall. any idea on how allow that external calls pass thru ??