[SR-Users] SEMS with sbc application

[Mojtaba]

Hello,
I have a problem today, It's strange for me.
Suppose we have this senario:
uac1------->SEMS(mo profile)------->Kamailio-------->SEMS(mt
profile)---------->uac2

In above topology, we have two interfaces(intern,extern) for SEMS, and
just used as SBC (sbc application).
if i used port=5060 as external port, every things is right and log
file is like this:
 [#7fed3f9f9700/32820] [run, udp_trsp.cpp:352] DEBUG: vv M [|] u recvd
msg via UDP from 89.165.117.125:42411 vv
--++--
REGISTER sip:kava.shatel.ir;transport=UDP SIP/2.0
Via: SIP/2.0/UDP
89.165.117.125:42411;branch=z9hG4bK-d8754z-021bd8b61efc7ac0-1---d8754z-
Max-Forwards: 70
Contact: <sip:4000@
89.165.117.125:42411;rinstance=79011092e56e1a09;transport=UDP>
To: <sip:4000 at kava.shatel.ir;transport=UDP>
From: <sip:4000 at kava.shatel.ir;transport=UDP>;tag=82820e1f
Call-ID: Y2U4YThiYjEwNTUzMzliZTIwNWZkMDI3MTM4OTZlNWU.
CSeq: 2 REGISTER
Expires: 3600
Allow: INVITE, ACK, CANCEL, BYE, NOTIFY, REFER, MESSAGE, OPTIONS,
INFO, SUBSCRIBE
Supported: replaces, norefersub, extended-refer, timer, X-cisco-serviceuri
User-Agent: Z 3.3.25608 r25552
Allow-Events: presence, kpml
Content-Length: 0

but when i  changed port=4080 for external port, The Via header and
contact header are changed to my public ip, like this:

 [#7fed3f9f9700/32820] [run, udp_trsp.cpp:352] DEBUG: vv M [|] u recvd
msg via UDP from 89.165.117.125:42411 vv
--++--
REGISTER sip:kava.shatel.ir;transport=UDP SIP/2.0
Via: SIP/2.0/UDP
172.1.1.125:42411;branch=z9hG4bK-d8754z-021bd8b61efc7ac0-1---d8754z-
Max-Forwards: 70
Contact: <sip:4000 at 172.1.1.125:42411;rinstance=79011092e56e1a09;transport=UDP>
To: <sip:4000 at kava.shatel.ir;transport=UDP>
From: <sip:4000 at kava.shatel.ir;transport=UDP>;tag=82820e1f
Call-ID: Y2U4YThiYjEwNTUzMzliZTIwNWZkMDI3MTM4OTZlNWU.
CSeq: 2 REGISTER
Expires: 3600
Allow: INVITE, ACK, CANCEL, BYE, NOTIFY, REFER, MESSAGE, OPTIONS,
INFO, SUBSCRIBE
Supported: replaces, norefersub, extended-refer, timer, X-cisco-serviceuri
User-Agent: Z 3.3.25608 r25552
Allow-Events: presence, kpml
Content-Length: 0
Why my public ip address is there here? I just changed external
port=4080 in sems server. In SDP protocol i have the same problem when
i changed external ip port in sems server.

Thanks.
--Mojtaba Esfandiari.S