Configuration of Sonicwall:
1) Setup the NAT on the Sonicwall to map traffic from an outside IP, we used a one to one type NAT in this example not PAT. Create the NAT as shown in this example, there will be a checkbox near the bottom that says “create reflexive policy” be sure this is checked as well and it will create the reflexive NAT automatically which tends to work better. You will need to configure the address objects beforehand ex: 172.18.200.1 = Router LAN IP. Your inbound interface may vary.
2) Create the firewall policy to allow the SIP traffic through to the outside IP address that you have NAT’ed to the proper inside address of the voice gateway. In this screenshot we have the service set to ANY, this was during testing. I would lock that down to only SIP for the final configuration.
3) Configure the VOIP settings in the firewall to match this screenshot. These settings corrected an issue when an outside party hung up the phone the call would continue for the internal party.
4) In Communication Manager the Gateway configuration should look similar to this taking into account any specific changes you need to make for your particular installation. The key settings to work out calls connecting properly with Triad Telecom’s implementation of SIP were to make sure you uncheck “Wait for Far-End H.245” and make sure you check “ Enable Inbound Fast-Start”
