title: Asterisk: Can call and answer but no voice or video
body: <p>I set up a simple asterisk server on a debian server.<br>
  My goal is to make two android phones call each other, using voice and later video, on my asterisk server.   Actually they are connected via 3G/4G network, and I use imsDroid softphone.  </p>
  
  <p><strong>I can make both phones call each other, I can answer the call on both ends.
  But I can't hear anything nor see any video.</strong><br>
  I'm a beginner using SIP protocol and asterisk. I may have configured asterisk or the softphones badly.</p>
  
  <p><strong>Do you know how to resolve this issue ? Or even how to debug it ?</strong>  Thanks!</p>
  
  <p>sip.conf:</p>
  
  <pre><code>[general]
  context=internal
  allowguest=no
  allowoverlap=no
  bindport=5060
  bindaddr=0.0.0.0
  srvlookup=no
  disallow=all
  allow=ulaw
  alwaysauthreject=yes
  canreinvite=no
  nat=yes
  session-timers=refuse
  localnet=192.168.1.0/255.255.255.0
  
  
  [7001]
  type=friend
  host=dynamic
  secret=123
  context=internal
  
  [7002]
  type=friend
  host=dynamic
  secret=456
  context=internal
  </code></pre>
  
  <p>extensions.conf:</p>
  
  <pre><code>[internal]
  exten =&gt; 7001,1,Answer()
  exten =&gt; 7001,2,Dial(SIP/7001,60)
  exten =&gt; 7001,3,Playback(vm-nobodyavail)
  exten =&gt; 7001,4,VoiceMail(7001@main)
  exten =&gt; 7001,5,Hangup()
  
  exten =&gt; 7002,1,Answer()
  exten =&gt; 7002,2,Dial(SIP/7002,60)
  exten =&gt; 7002,3,Playback(vm-nobodyavail)
  exten =&gt; 7002,4,VoiceMail(7002@main)
  exten =&gt; 7002,5,Hangup()
  
  exten =&gt; 8001,1,VoicemailMain(7001@main)
  exten =&gt; 8001,2,Hangup()
  
  exten =&gt; 8002,1,VoicemailMain(7002@main)
  exten =&gt; 8002,2,Hangup()
  </code></pre>
  
  <p>modules.conf:</p>
  
  <pre><code>[modules]
  autoload=no
  load=pbx_config.so
  load=chan_sip.so
  load=chan_iax2.so
  load=res_rtp_asterisk.so
  load=app_hangup.so
  load=app_dial.so
  load=codec_ulaw.so
  load=codec_gsm.so
  </code></pre>