Need help with firewall settings on At&t fiber and Sonicwall firewall

[blockhard]

I have had two different platinum partners try to resolve but no luck yet.

My setup is:

3CX running as VM on a ESXi computer
Internet modem is a Arris BGW210-700 with At&t fiber (all firewall is set to off)
Firewall is a SonicWall TZ400 running firmware 6.5.1.2-52n (setup of firewall for 3CX done by both the partners above but did not vary from one to the other)

I am getting the "full cone test failed" on all the ports.

Please help.

 

[pmterp]

I believe the issue has to do with the AT&T issued Arris not having an actual bridge mode.
Here's a link to some guidance on accomplishing a bridge mode equivalent with the Arris.
https://forums.att.com/t5/AT-T-Inte...P-Passthrough-Can-I-enable-on-my/td-p/5296974
Scroll down to the post from rreddy on May 15, 2017 9:41 PM and the few posts after that.