If you have upgraded your version of Asterisk and find that your IAX2 extensions no longer work then the cause could be a change to the IAX protocol. This was made to resolve a security issue that could result in a denial of service attack.
You will see this error in the Asterisk log file if you are suffering from this issue –
If you use FreePBX then Asterisk can be made to function the same as before by adding the following 2 lines to /etc/asterisk/iax_general_custom.conf –
maxcallnumbers = 16382
You will also need to do a –
or restart Asterisk for the changes to take effect.
More information about the reason for this change and the implications for disabling call token checking can be found here –