Configuring an AVM FritzBox

[KaterinaK_3CX]

Read the guide.

 

[ThatsMe]

Is this the valid setup, the Firewall check does not work with this setup on a FritzBox, any suggestions?
I have fixed ip address, do i need dns entry for it or just the xxxx.my3cx.de?

 

[ChrisC_3CX]

Is this the valid setup, the Firewall check does not work with this setup on a FritzBox, any suggestions?
I have fixed ip address, do i need dns entry for it or just the xxxx.my3cx.de?

Do you happen to be using the same FritzBox model and running the same firmware version as mentioned in the guide? If yes then it should apply otherwise there might be some differences depending on what model and firmware you're running.

If you're using a 3CX FQDN then a DNS entry should already exist as it is 3CX that manages the DNS in such cases. What exactly fails when you run the firewall checker? Could you provide a screenshot of the results?

 

[ThatsMe]

Hi Chris,
sure this is not the same Box and not the same Version, i keep my stuff up to date to be secure. The FritzBox is a 7590 and the Version is 7.28. Attached the Fritzbox port forwarding setup and the output of the Firewall check. Will be nice if you could help me, iam currently lost and have no more ideas. The firewall errors even occurs if i setup the host as an exposed host. The 3CX runs with Port 5062 while the Fritzbox uses 5060.
Thanks

 

[ChrisC_3CX]

This seems like some kind of port remapping feature. I'd recommend checking the FritzBox settings for such services/features, maybe under security/firewall settings or some other similar section on the FritzBox's UI to see if you can find anything enabled that might be causing this.

 

[ThatsMe]

There is no more security/firewall setups on the FritzBox, it's all done for Beginners, even in the expert mode. There are more port forwardings for my SMA Solarsystem, these are working fine and no problems. But sure different ports and ip addresses. I do not have anymore any idea? As i mentioned even if i completly open the host (exposed) the firewall checker won't be succesful.

 

[ChrisC_3CX]

The fact that you see the "Mapping does not match" error when running the firewall checker most definitely means something in between 3CX and our STUN servers used for the firewall test is affecting the traffic.

I'd recommend first consulting the firewalls documentation to confirm that there are no other settings that may be contributing to this issue such as SIP ALG, port remapping or something else that might be affecting port preservation. If not, and you still can't reach a resolution, you might want to consider contacting one of our 3CX Partners who have experience with these kinds of issues.

Note: You might also want to take a look at our documentation on how the 3CX Firewall checker works to hopefully help clear up the situation: https://www.3cx.com/docs/firewall-checker/

 

[ThatsMe]

Do you recommend any Modem/Router Hardware which really works ? FritzBox is one of the most used Modem/Router solution, why is this not fully supported? What 3CX is using in their labs?

 

[ChrisC_3CX]

Do you recommend any Modem/Router Hardware which really works ? FritzBox is one of the most used Modem/Router solution, why is this not fully supported?

It is not a case of not supporting the specific FritzBox as we do not support any particular firewalls and therefore cannot suggest anything specific. The guides were created for the most commonly used firewalls or at least most commonly used by our customers to help as much as we can even though this task actually falls out of 3CX's scope.

The port requirements should be sufficient information to configure the firewall along with the info in our guide and our suggestions regarding disabling services such as SIP ALG, port remapping, etc.

If for any reason such services are enabled and cannot be modified I'm afraid there's not much we can do. Only thing I can suggest is checking this with the firewall vendor or the ISP in case restrictions are in place to what can and cannot be modified in regards to the device's configuration.