iax2.conf

[guest]
type=user
context=iaxguest-in

extensions.conf

[iaxguest-in]
exten => _X.,1,Dial(SCCP/100,30)
exten => _X.,n,Congestion()


Rx-Frame Retry[ No] -- OSeqno: 000 ISeqno: 000 Type: IAX     Subclass: NEW    
   Timestamp: 00006ms  SCall: 00052  DCall: 00000 [213.166.5.129:4569]
   VERSION         : 2
   CALLED NUMBER   : 44844xxxxxxx
   CODEC_PREFS     : (alaw|ulaw|gsm|ilbc)
   CALLING NUMBER  : 0031xxxxxxxxx
   CALLING PRESNTN : 0
   CALLING TYPEOFN : 0
   CALLING TRANSIT : 0
   LANGUAGE        : en
   USERNAME        : foobar
   FORMAT          : 8
   CAPABILITY      : 64526
   ADSICPE         : 2
   DATE TIME       : 2007-10-05  03:05:26

Oct  5 04:05:26 NOTICE[18008]: chan_iax2.c:6977 socket_read: Rejected connect attempt from 213.166.5.129, who was trying to reach '44844xxxxxxx@'
Tx-Frame Retry[000] -- OSeqno: 000 ISeqno: 001 Type: IAX     Subclass: REJECT 
   Timestamp: 00012ms  SCall: 00004  DCall: 00052 [213.166.5.129:4569]
   CAUSE           : No authority found
   CAUSE CODE      : 50