Hi all,

I have a one question regarding ACK and Proxy-Authorization header.

I am testing Kamailio 3.3 as SIP proxy,default config. I made one call with 2 phones where one has Public IP while other is behind NAT. SIP clients are Panasonic KX-UT133 and other is 1-NET (ex Sweden Mobile&CDMA provider ,over 50M users) Everything is working just fine, both RTP and SIP. On the other hand one of the clients,1-NET one, send Proxy-Authorization in ACK when he receives 200 OK from Kamailio.

PUBLIC_IP_USER1 – user 1000

PUBLIC_IP_USER2 – user 1001

KAMAILIO è 1-NET

SIP/2.0 200 OKr\n

Record-Route: <sip:KAMAILIO_PUBLIC_IP;lr=on;nat=yes>

Via: SIP/2.0/UDP PUBLIC_IP_USER1:5064;rport=5064;branch=z9hG4bK934894606

Call-ID: 221374358

From: blabla <sip:1000@KAMAILIO_PUBLIC_IP>;tag=507511069

To: <sip:1001@KAMAILIO_PUBLIC_IP:5060>;tag=2148378512

CSeq: 21 INVITE

Allow: INVITE,ACK,CANCEL,BYE,INFO,UPDATE,OPTIONS,NOTIFY,REFER

Contact: <sip:1001@PUBLIC_IP_USER2:1027>

Require: replaces

Content-Type: application/sdp

Server: Panasonic_KX-UT133NE/01.081 (0080f0cedd83)

Content-Length: 182

v=0

o=- 1343736535 1343736535 IN IP4 KAMAILIO_PUBLIC_IP

s=-

c=IN IP4 KAMAILIO_PUBLIC_IP

t=0 0

m=audio 20412 RTP/AVP 18

a=rtpmap:18 G729/8000

a=sendrecv

a=ptime:20

a=nortpproxy:yes

1-NET è KAMAILIO

ACK sip:1001@PUBLIC_IP_USER2:1027 SIP/2.0

Via: SIP/2.0/UDP PUBLIC_IP_USER1:5064;rport;branch=z9hG4bK642028490

Route: <sip:KAMAILIO_PUBLIC_IP;lr=on;nat=yes>

From: blabla <sip:1000@KAMAILIO_PUBLIC_IP>;tag=507511069

To: <sip:1001@KAMAILIO_PUBLIC_IP:5060>;tag=2148378512

Call-ID: 221374358

CSeq: 21 ACK

Contact: <sip:1000@PUBLIC_IP_USER1:5064>

[truncated] Proxy-Authorization: Digest username="1000", realm="KAMAILIO_PUBLIC_IP", nonce="UBfL8lAXysb5tJCs80ZnthyPl9IzmRZk", uri="sip:1001@KAMAILIO_PUBLIC_IP:5060", response="7824519cdad9f1c2c79027a2d7522344", algorithm=MD5, cnonce="0a4f113b", q

Max-Forwards: 70

User-Agent: Serbia_2.00

Content-Length: 0

I attach txt file with call flow, I can send pcap also.

I think that the issue is related with bad client but I need another opinion.

Does anyone has an idea about this issue?

Best Regards,

Ivan