[MrX87]

ho modificato l'INVITE come detto da te in questo modo:

"INVITE sip:"+number_dest+"@"+addr_dest+" SIP/2.0\r\n"+
					 "Via: SIP/2.0/UDP "+addr_dest+":5060;rport;branch=z9hG4bKnvjeoqua\r\n"+
					 "Max-Forwards: 70\r\n"+
					 "To: <sip:"+number_dest+"@"+addr_dest+">\r\n"+
					 "From: "+number_dest+" <sip:"+number_dest+"@"+addr_src+">;tag=ycbzi\r\n"+
					 "Call-ID: "+number_dest+"@"+addr_src+"\r\n"+
					 "CSeq: 976 INVITE\r\n"+
					 "Contact: <sip:"+number_dest+"@"+addr_src+":5060>\r\n"+
					 "Content-Type: application/sdp\r\n"+
					 "Allow: INVITE,ACK,BYE,CANCEL,OPTIONS,PRACK,REFER,NOTIFY,SUBSCRIBE,INFO,MESSAGE\r\n"+
					 "Supported: replaces,norefersub,100rel\r\n"+
					 "User-Agent: My_pc\r\n"+
					 "Content-Length: 254\r\n"+
					 "\r\n"+
					 "2v=0\r\n"+
					 "o=My_pc 105015165 105015162 IN IP4 "+addr_src+"\r\n"+
					 "s=-\r\n"+
					 "c=IN IP4 "+addr_src+"\r\n"+
					 "t=0 0\r\n"+
					 "m=audio 8000 RTP/AVP 8 0 3 101\r\n"+
					 "a=rtpmap:8 PCMA/8000\r\n"+
					 "a=rtpmap:0 PCMU/8000\r\n"+
					 "a=rtpmap:3 GSM/8000\r\n"+
					 "a=rtpmap:101 telephone-event/8000\r\n"+
					 "a=fmtp:101 0-15\r\n"+
					 "a=ptime:20\r\n"+
		 			 "\r\n";

inoltre ho configurato il file di asterisk extension.conf aggiungendo al fondo questo:

exten => 100,1,Answer
exten => 100,n,Echo
exten => 100,n,Hangup

dove ovviamente 100 è il numero che chiamo che corrisponde a number_dest.

con questa configurazione asterisk mi risponde che l'indirizzo è incompleto:

SIP/2.0 484 Address Incomplete
Via: SIP/2.0/UDP 192.168.1.228:5061;branch=z9hG4bKnvjeoqua;received=192.168.1.102;rport=44864
From: 100 <sip:100@192.168.1.102>;tag=ycbzi
To: <sip:200@192.168.1.228>;tag=as4245b09d
Call-ID: 100@192.168.1.102
CSeq: 976 INVITE
User-Agent: Asterisk PBX
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY
Content-Length: 0