Hi All
After reading through all the VOIP related posts I could find
And trying every possible combination of NAT to get my 3CX PBX server to register but without any success I have finally came to the following conclusions:
- If I connect my PBX server directly to the internet it registers fine (via USB tethering on my Android phone), so there must be some problem with the UTM 9 gateway and the NATing.
- I tried all combinations under Network Protection -> VOIP, still doesn't register.
- If I look at the Firewall packets the traffic only goes out to the VOIP provider but no packets are received from that IP address. (My STUN servers resolve my external IP address fine, no problems there)
The last fact suggest to me that the UTM 9 somehow changes the SIP header/packet, and from some related searches points to me that the source port is being translated? And for SIP comms Port preservation is required?
My final attempt to find this problem would be to setup a remote server listening on 5060 and compare the SIP register request packets when the PBX server is behind the UTM 9 Gateway or not. This might be time consuming so I will also instead ask my VOIP provider with some Wireshark logs fom my IP if that is possible...
This setup worked fine on PfSense so I can't understand what might be different now, any ideas would be greatly appreciated?
Regards
Johan
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