Is your Asterisk box behind a router? Using SIP? If so read:

This caused me sooo many hours of grief.

If you try to make SIP calls over the Internet, but your Asterisk box is behind a router, you may experience a problem where the call will connect but you won’t hear any voice. Here is what you have to do to fix it:

  • Go to your rtp.conf file and note the values for rtpstart and rtpend

  • On your router, add port forwarding for the SIP port (5060) and for the entire range of ports between rtpstart and rtpend.

  • Find your EXTERNAL IP address by clicking this link:

  • Go to your sip.conf file and add the following under the [general] context:

externip= (replace with your external ip address)
localnet= (replace with your local network address and mask)

  • restart asterisk

Good luck!