VoIP faxing T.38 issues

[riddlebox]

Hello everyone,
I put in an OPNSense router and now my faxes have stopped working over VoIP.

I put my original router back in place and the faxes successfully send.

I am still very new to OPNSense so I am not sure where to start troubleshooting the issue.

Any guidance on how would be very much appreciated! I also searched the forums and the web and did not see any references to T.38.

[riddlebox]

Hello,
Just wanted to update anyone. I got a list of all servers my provider uses and created an alias with them and then created a firewall nat rule to allow traffic from my providers servers to my PBX and everything including faxes now works properly.