GAMMA SIP - outbound calls working, inbound calls failing

[MarkCSUK]

Our client is running a locally hosted (on premise) 3CX v20 (U4 B487) Standard Annual 4 Simultaneous Calls

All services are running, firewall test fully passes.

Outbound calls are working, but inbound calls do not appear to connect,
I see no inbound connection from GAMMA on 5060 or any other SIP Port when calling in.

GAMMA are adamant that the fault is at the client end - but I'm stuck as where to look.

I'm just thinking that if the firewall isnt even showing a connection attempt the issue must be at the GAMMA end.

Just need a sanity check really - and any advice.

 

[YiannisH_3CX]

If you do not see any traffic from Gamma coming to your system/firewall then not much we can do on the 3CX side. Perhaps they don't have the right IP address? Since Gamma is registration based then they need to know your IP of FQDN to send calls to you. If there is no traffic then you definitely need to talk to Gamma. Once traffic starts hitting your system then we can look at the 3CX side.
If you have a custom FQDN then make sure if resolves correctly or if you have double WAN connections check both for traffic. Either than that not much we can advise.

 

[MarkCSUK]

Hi Yiannis,

Thank you - yes only a single inbound line - the outbound calls are working - the GAMMA gateway accepts traffic from the IP (which is a GAMMA broadband line to rub salt in the wound), the IP is set correctly on the GAMMA end, but they insist the fault is our end.

I'll go back to them emboldend by the fact that I'm in the right thank you!