I have installed AsteriskNow server with FreePBX on Virtualbox. I am using a Softphone(3cxphone) to test the system. I could able to connect to Asterisk and make calls. But I can't here anything what other end is saying. Also the call is got cut after 8-10 seconds.

I configured and tested my microphone and it is working properly.


  • Have you checked for blocked firewall ports? If you are doing this in an isolated environment (not connected to the internet), try disabling all firewalls as a quick easy test to confirm whether or not it is a firewall issue. Also, is this noticed on both sides of the phone conversation or just one way? – David Jan 22 '14 at 2:28

The problem is that the firewall is blocked the RTP (and RTCP) traffic. The session is established with SIP, hence you can do calls and receive calls but You dont listen, because the media traffic is blocked. Then, You should open the /etc/asterisk/rtp.conf file and edit the follow lines with the ports that You want use to RTP (and RTCP) protocol.


RTP protocol works over UDP, then You should open this UDP port range. (In your Server and if You are using NAT You should configure the port forwarding too.


You need configure nat and firewall


  • I configured them, but it is stll not working – Harikrishnan Jan 18 '14 at 6:19
  • Probably you need network expert or asterisk expert. Note, asterisk in virtualization is not for begginer. – arheops Jan 18 '14 at 11:43

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.