Jitsi #1 -> sip2sip.info -> Kamailio edge proxy -> Kamailio registrar -> Kamailio edge proxy -> Jitsi #2

SIP/2.0 200 OK
To: <sip:...callee...@...callee domain...>;tag=e5116094
Via: SIP/2.0/UDP 81.23.228.129:5060;rport=5060;branch=z9hG4bKdb93.87290485.0;i=0efbc,SIP/2.0/TLS 192.168.0.135:52379;rport=52379;received=a.b.c.d;branch=z9hG4bK-363631-23ca624fe9c119f229080992ed4fc143
Record-Route: <sip:Rlwj4KMCy9UUUAMK9JufE8VamABismk=@e.f.g.h:5061;transport=tls;r2=on;lr=on>,<sip:Rlwj4KMCy9UUUAMK9JufE8VamABismk=@10.244.155.159:5080;transport=tcp;r2=on;lr=on>,<sip:10.101.62.154;transport=tcp;lr=on>,<sip:10.244.155.159:5080;transport=tcp;r2=on;lr=on>,<sip:e.f.g.h;r2=on;lr=on>,<sip:81.23.228.129;r2=on;lr;ftag=2d246de3;did=989.4a20eb73>,<sip:81.23.228.129:5061;transport=tls;r2=on;lr;ftag=2d246de3;did=989.4a20eb73>
CSeq: 2 INVITE
Call-ID: 38135c0b82a8a7d571352350d207b943@0:0:0:0:0:0:0:0
From: "Caller" <sip:...caller...@sip2sip.info>;tag=2d246de3
Contact: "callee" <sip:...callee...@10.6.201.224:60847;transport=tls;registering_acc=...callee domain...>
User-Agent: Jitsi2.3.4622.9647Linux
Content-Type: application/sdp
Content-Length: 838

...lots of SDP...

ACK sip:...callee...@174.129.184.181:5060;transport=tls;registering_acc=...callee domain... SIP/2.0
Call-ID: 38135c0b82a8a7d571352350d207b943@0:0:0:0:0:0:0:0
CSeq: 2 ACK
Via: SIP/2.0/UDP 81.23.228.129:5060;branch=z9hG4bKdb93.87290485.2;i=0efbc
Via: SIP/2.0/TLS 192.168.0.135:52379;rport=52379;received=a.b.c.d;branch=z9hG4bK-363631-212696616e66a14286e3165485387895
From: "Caller" <sip:...caller...@sip2sip.info>;tag=2d246de3
To: "callee" <sip:...callee...@...callee domain...>;tag=e5116094
Max-Forwards: 69
Route: <sip:e.f.g.h;r2=on;lr=on>,<sip:10.244.155.159:5080;transport=tcp;r2=on;lr=on>,<sip:10.101.62.154;transport=tcp;lr=on>,<sip:Rlwj4KMCy9UUUAMK9JufE8VamABismk=@10.244.155.159:5080;transport=tcp;r2=on;lr=on>,<sip:Rlwj4KMCy9UUUAMK9JufE8VamABismk=@e.f.g.h:5061;transport=tls;r2=on;lr=on>
Contact: "Caller" <sip:...caller...@90.152.0.102:52379;transport=tls;registering_acc=sip2sip_info>
User-Agent: Jitsi2.2.4603.9615Windows 7
Content-Length: 0

ACK sip:Rlwj4KMCy9UUUAMK9JufE8VamABismk=@e.f.g.h:5061;transport=tls;r2=on;lr=on SIP/2.0
Call-ID: 38135c0b82a8a7d571352350d207b943@0:0:0:0:0:0:0:0
CSeq: 2 ACK
Via: SIP/2.0/TCP e.f.g.h:5060;branch=z9hG4bKdb93.444f42f24139f6dc512d70f61ca64be4.0
Via: SIP/2.0/UDP 81.23.228.129:5060;rport=5060;branch=z9hG4bKdb93.87290485.2;i=0efbc
Via: SIP/2.0/TLS 192.168.0.135:52379;rport=52379;received=a.b.c.d;branch=z9hG4bK-363631-212696616e66a14286e3165485387895
From: "Caller" <sip:...caller...@sip2sip.info>;tag=2d246de3
To: "callee" <sip:...callee...@...callee domain...>;tag=e5116094
Max-Forwards: 16
Route: <sip:10.244.155.159:5080;transport=tcp;r2=on;lr=on>,<sip:10.101.62.154;transport=tcp;lr=on>,<sip:Rlwj4KMCy9UUUAMK9JufE8VamABismk=@10.244.155.159:5080;transport=tcp;r2=on;lr=on>
Contact: "Caller" <sip:...caller...@a.b.c.d:52379;transport=tls;registering_acc=sip2sip_info>
User-Agent: Jitsi2.2.4603.9615Windows 7
Content-Length: 0

request_route {
	route(REQINIT);

	route(OPTIONS);

	sip_trace();
	setflag(F_SIPTRACE);

        if (is_method("CANCEL")) {
		if (t_check_trans()) {
			route(RELAY);
		}
		exit;
	}

	route(WITHINDLG);
	...


route[WITHINDLG] {
	if (has_totag()) {
		if (!loose_route()) {
			switch($rc) {
			case -2:
				send_reply("403", "Forbidden");
				exit;
			default:
				if (is_method("ACK")) {
					if ( t_check_trans() ) {
						route(RELAY);
						exit;
					} else {
						exit;
					}
				}
				send_reply("404","Not Found");
			}
		} else {
			if ($rc == 2) {
				setflag(F_OB_DRIVEN);
			}

			if (is_method("NOTIFY")) {
				record_route();
			}
			route(RELAY);
		}
		exit;
	}
}