Greetings. We have NV3120 running R12.2.0 and an Avaya PBX with SIP trunks that are unhappy. The challenge is that the firewall constantly changes the UPD port, which messes with the signaling. The carriers SBC mostly fixes it, but we know that it's not correct.. The PBX knows the public address, and can generate appropriate SIP headers, so we generally don't need ALG or proxy. We've tried dozens of iterations with no joy (with/without ALG and proxy settings). We've tried "ip firewall source-port-preservation record-source-address". There is only one PBX at our site, communicating with one provider out there in the world. We're looking for UDP 5060 to be sent thru the firewall without being changed, and we would welcome any magic. Thanks in advance!
Oh - and in my actual config, I used the (I believe) correct "ip firewall nat-preserve-source-port record-source-address".