I appreciate this question is quite "out-there" but - has anyone had any success with VOIP over SIP behind a SonicWALL. We are having an issue with one-way audio inbound.
Essentially, the person calling (or called) can hear me (from the phone on the same LAN as the PBX), but we cannot hear them. Packet captures show the RTP traffic coming back to the Sonic and destined for the PBX but it simply cannot be reaching it. My understanding is SonicWALLs use Symmetric NAT and this is the problem as STUN doesn't work with this type of NAT.
Is there any workaround or anyone here with any success?