[Serusers] TCP/TLS and NAT. Problem with BYE...

Sat Oct 15 19:31:55 CEST 2005

Hi everybody,

A short question:

alice at atlanta.com is behind NAT. She uses TCP to connect her UAC to 
sip.atlanta.com in the public network.
Inviting bob at biloxi.com suceeds. But Bob can't terminate the call. His 
BYE is not routed back, because fix_nated_contact() does only work with 
UDP. And Bob builds the R-URI with the Infos of Alice's contact header.

The route is as follows:
alice at atlanta.com [172.16.0.4] -> natbox.atlanta.com [172.16.0.1 | 
192.168.0.13] -> sip.atlanta.com [192.168.0.14] -> sip.biloxi.com 
[192.168.1.14] -> bob at biloxi.com [192.168.1.1]

Possible solutions:
- force_tcp_alias() -> but reading the draft 
draft-ietf-sip-connect-reuse-04.txt yields that this must be supported 
by the components - so doesn't the snom360 of Alice
- commenting some lines in nathelper.c and activate it for TCP -> this 
works pretty fine and the BYE finds its way from Bob through the NAT-Box 
to Alice. But this is a dirty solution.

So does anybody has a similar problem? My config works fine with UDP but 
switching to TCP makes life hard...
I attached the traces Bob received, his last BYE is finally dropped by 
sip.atlanta.com, because the network-address 172.16.0.4 can't be found!

Thank you for your help!
regards, Philipp

=========================================================================

Received from tcp:192.168.1.14:5060 at 15/10/2005 19:18:32:250 (1751 bytes):

INVITE sip:bob at 192.168.1.1:2063;transport=tcp;line=wxqurd1s SIP/2.0
Record-Route: <sip:192.168.1.14;transport=tcp;r2=on;ftag=5s8qncdbso;lr=on>
Record-Route: 
<sip:192.168.1.14:5061;transport=tls;r2=on;ftag=5s8qncdbso;lr=on>
Record-Route: 
<sip:192.168.0.14:5061;transport=tls;r2=on;ftag=5s8qncdbso;lr=on>
Record-Route: <sip:192.168.0.14;transport=tcp;r2=on;ftag=5s8qncdbso;lr=on>
Via: SIP/2.0/TCP 192.168.1.14;branch=z9hG4bKcad9.057cd815.0;i=d
Via: SIP/2.0/TLS 192.168.0.14:5061;branch=z9hG4bKcad9.685be3c3.0;i=1
Via: SIP/2.0/TCP 
172.16.0.4:2327;received=192.168.0.13;branch=z9hG4bK-y79imu6dlqxs;rport=2327
From: "Alice" <sip:alice at atlanta.com>;tag=5s8qncdbso
To: <sip:bob at biloxi.com>
Call-ID: 3c2675cac832-ce5ge5sxlx2q at snom360
CSeq: 1 INVITE
Max-Forwards: 68
Contact: <sip:alice at 172.16.0.4:2327;transport=tcp;line=fyyuh6tl>
P-Key-Flags: resolution="31x13", keys="4"
User-Agent: snom360/4.3
Accept: application/sdp
Allow: INVITE, ACK, CANCEL, BYE, REFER, OPTIONS, NOTIFY, SUBSCRIBE, 
PRACK, MESSAGE, INFO
Allow-Events: talk, hold, refer
Supported: timer, 100rel, replaces, callerid
Session-Expires: 3600
Content-Type: application/sdp
Content-Length: 507
P-hint: outbound
P-hint: forced TLS relay
P-hint: usrloc applied

Sent to tcp:192.168.1.14:5060 at 15/10/2005 19:18:32:270 (929 bytes):

SIP/2.0 180 Ringing
Via: SIP/2.0/TCP 192.168.1.14;branch=z9hG4bKcad9.057cd815.0;i=d
Via: SIP/2.0/TLS 192.168.0.14:5061;branch=z9hG4bKcad9.685be3c3.0;i=1
Via: SIP/2.0/TCP 
172.16.0.4:2327;received=192.168.0.13;branch=z9hG4bK-y79imu6dlqxs;rport=2327
Record-Route: <sip:192.168.1.14;transport=tcp;r2=on;ftag=5s8qncdbso;lr=on>
Record-Route: 
<sip:192.168.1.14:5061;transport=tls;r2=on;ftag=5s8qncdbso;lr=on>
Record-Route: 
<sip:192.168.0.14:5061;transport=tls;r2=on;ftag=5s8qncdbso;lr=on>
Record-Route: <sip:192.168.0.14;transport=tcp;r2=on;ftag=5s8qncdbso;lr=on>
From: "Alice" <sip:alice at atlanta.com>;tag=5s8qncdbso
To: <sip:bob at biloxi.com>;tag=fxdufnc4xz
Call-ID: 3c2675cac832-ce5ge5sxlx2q at snom360
CSeq: 1 INVITE
Contact: <sip:bob at 192.168.1.1:2063;transport=tcp;line=wxqurd1s>
Allow: INVITE, ACK, CANCEL, BYE, REFER, OPTIONS, NOTIFY, SUBSCRIBE, 
PRACK, MESSAGE, INFO
Allow-Events: talk, hold, refer
Content-Length: 0

Sent to tcp:192.168.1.14:5060 at 15/10/2005 19:18:33:390 (1377 bytes):

SIP/2.0 200 Ok
Via: SIP/2.0/TCP 192.168.1.14;branch=z9hG4bKcad9.057cd815.0;i=d
Via: SIP/2.0/TLS 192.168.0.14:5061;branch=z9hG4bKcad9.685be3c3.0;i=1
Via: SIP/2.0/TCP 
172.16.0.4:2327;received=192.168.0.13;branch=z9hG4bK-y79imu6dlqxs;rport=2327
Record-Route: <sip:192.168.1.14;transport=tcp;r2=on;ftag=5s8qncdbso;lr=on>
Record-Route: 
<sip:192.168.1.14:5061;transport=tls;r2=on;ftag=5s8qncdbso;lr=on>
Record-Route: 
<sip:192.168.0.14:5061;transport=tls;r2=on;ftag=5s8qncdbso;lr=on>
Record-Route: <sip:192.168.0.14;transport=tcp;r2=on;ftag=5s8qncdbso;lr=on>
From: "Alice" <sip:alice at atlanta.com>;tag=5s8qncdbso
To: <sip:bob at biloxi.com>;tag=fxdufnc4xz
Call-ID: 3c2675cac832-ce5ge5sxlx2q at snom360
CSeq: 1 INVITE
Contact: <sip:bob at 192.168.1.1:2063;transport=tcp;line=wxqurd1s>
Require: timer
Session-Expires: 3600;refresher=uac
User-Agent: snom360/4.3
Allow: INVITE, ACK, CANCEL, BYE, REFER, OPTIONS, NOTIFY, SUBSCRIBE, 
PRACK, MESSAGE, INFO
Allow-Events: talk, hold, refer
Supported: timer, 100rel, replaces, callerid
Content-Type: application/sdp
Content-Length: 296

ACK sip:bob at 192.168.1.1:2063;transport=tcp;line=wxqurd1s SIP/2.0
Record-Route: <sip:192.168.1.14;transport=tcp;r2=on;ftag=5s8qncdbso;lr=on>
Record-Route: 
<sip:192.168.1.14:5061;transport=tls;r2=on;ftag=5s8qncdbso;lr=on>
Record-Route: 
<sip:192.168.0.14:5061;transport=tls;r2=on;ftag=5s8qncdbso;lr=on>
Record-Route: <sip:192.168.0.14;transport=tcp;r2=on;ftag=5s8qncdbso;lr=on>
Via: SIP/2.0/TCP 192.168.1.14;branch=0;i=d
Via: SIP/2.0/TLS 192.168.0.14:5061;branch=0;i=1
Via: SIP/2.0/TCP 
172.16.0.4:2327;received=192.168.0.13;branch=z9hG4bK-o9f1lglhf4pk;rport=2327
From: "Alice" <sip:alice at atlanta.com>;tag=5s8qncdbso
To: <sip:bob at biloxi.com>;tag=fxdufnc4xz
Call-ID: 3c2675cac832-ce5ge5sxlx2q at snom360
CSeq: 1 ACK
Max-Forwards: 68
Contact: <sip:alice at 172.16.0.4:2327;transport=tcp;line=fyyuh6tl>
Content-Length: 0
P-hint: rr-enforced
P-hint: rr-enforced

Sent to tcp:192.168.1.14:5060 at 15/10/2005 19:18:34:480 (703 bytes):

BYE sip:alice at 172.16.0.4:2327;transport=tcp;line=fyyuh6tl SIP/2.0
Via: SIP/2.0/TCP 192.168.1.1:2063;branch=z9hG4bK-gu03sll9uumm;rport
Route: <sip:192.168.1.14;transport=tcp;r2=on;ftag=5s8qncdbso;lr=on>
Route: <sip:192.168.1.14:5061;transport=tls;r2=on;ftag=5s8qncdbso;lr=on>
Route: <sip:192.168.0.14:5061;transport=tls;r2=on;ftag=5s8qncdbso;lr=on>
Route: <sip:192.168.0.14;transport=tcp;r2=on;ftag=5s8qncdbso;lr=on>
From: <sip:bob at biloxi.com>;tag=fxdufnc4xz
To: "Alice" <sip:alice at atlanta.com>;tag=5s8qncdbso
Call-ID: 3c2675cac832-ce5ge5sxlx2q at snom360
CSeq: 1 BYE
Max-Forwards: 70
Contact: <sip:bob at 192.168.1.1:2063;transport=tcp;line=wxqurd1s>
User-Agent: snom360/4.3
Content-Length: 0