SIP-ALG must be switched off for Fonzer telephony. On many firewalls and routers this is on by default.
To investigate the status of SIP-ALG we have a tool (only works on Windows). Download the tool in attachment.
- Make sure the Windows machine is in the same network as the telephony network.
- Run the application
- Accept all permissions questions you get from the Windows machine
- The application will now run the tests
If the result is FALSE then SIP-ALG has not been detected by the application. This does not necessarily mean that it is off.
If the result is TRUE then SIP-ALG is active and must be switched off.