I’ve set up a UCM 6202 behind a Fritzbox (dynamic IP) with several IP phones in a local network. All is working quite perfectly. Because of having a dynamic IP I was forced to find a solution for a public IP - I’ve found it with the MyFritz!-service. This service will give you a cryptic domain like “dsd39dfj39.myfritz.net” which will be resolved as the current public IP. I’ve checked this with public DNS check tools and it works so no further DynDNS-service should be needed.
I’ve entered this url in my UCM 6202 under PBX Settings > SIP Settings - NAT - External Host.
In the Fritzbox I’ve activated port forwarding for the Grandstream UCM port 5070 (and for RTP some more ports. Unfortunately it is not possible to have ports 10000 - 20000 because Fritzbox only allows up to 250 port in one range only):
Next I’ve set up a new extension in the PBX
Then I’ve asked the PBX to send me the credentials for this extension by mail:
I’ve entered those credentials in the Phonerlite config:
and played around a bit with the settings. I’ve tried the local port on 5060 and 5070, I’ve used the “:5070” behind the “Proxy/Registrar” and didn’t use it, I’ve used the word “grandstream” in the field “Domain/Realm” (because it is shown here
But whatever I did - I was not able to connect to the UCM yet.
I’ve then used the local network to check whether the user credentials are 100% correct - they are. As soon as I am local and use the local IP of the PBX followed by the port (192.168.178.5:5070) it works. And it does not make a difference whether I use “grandstream” in “Domain/Realm” or not in this case. The local port is 5060 in the Phonelite settings here.
So the problem is the external connection. I checked the UCMs capture file to check for the IP of the client which shoudl try to connect but I was not able to find this IP in the packet. So my current thought is that the Fritzbox does not forward the client to the UCM at all but I do not know what to do at the moment. Hopefully anybody has an idea which can help?
Thanks in advance!