3CX Port Forwarding Issue

Hi Guys,

We use a 3CX Phone system with a SIP Trunk.

We are experiencing issues where calls make it through to the system maybe 3/5 times successfully then other times the call wont even make it to the 3CX server (No entries in call log) or the call will be picked up but there is no audio.

Previous to installing our XG Firewall the system worked flawlessly with the following ports forwarded from the Gateway Router to the 3CX Server IP Address

Forwarded ports to 192.168.0.80

TCP 5001

UDP 5060

TCP 5060

UDP  5090

TCP 5090

UDP 9000-9500

Since the XG is now our gateway i have set the following firewall rules. (The 3CX server address is now 172.16.16.80)

Using Business Application Rules -> DNAT/FULLNAT/LOAD BALANCE

See attached screenshot for sample rule on port 5060

Note that i also have the following checked:

- Rewrite source address

- Outbound Address MASQ

- Create reflexive rule

- Log Firewall traffic

For the life of me i cannot figure out why some calls work flawlessly and some just fail with no audio. I've checked through the firewall logs and nothing jumps out at me.

I do have the Allowed client Networks set to Australia only, but our voip provider is Australian and their IP is within the Aus Geographical zone.

Has anyone here got a working config with 3CX and a VOIP Provider?

nat