[Users] openser and rtpproxy on multihomed host

[Alexander Bergolth]

Hi!

I'm experiencing problems using openser and rtpproxy on a multihomed box
(IP addresses are 137.208.89.45 and 137.208.89.65).

The client (firewalled) contacts the server via the first IP address
(137.208.89.45) but rtpproxy sometimes uses it's second IP
(137.208.89.65) in the "c=" SDP-information. (See below.)
However it _sends_ RTP packets from the _first_ IP address. Those
packets will never pass through the firewall, of course, since the
clients outgoing RTP traffic is sent to another IP address than the
incoming traffic is hitting the firewall from.

Is there a way to tell rtpproxy to use the same IP-address both for the
c= SDP header and as source address?

-------------------- 8< --------------------
##
T 2007/06/05 15:57:36.041537 137.208.89.45:5060 -> 137.208.90.164:3099 [AP]
SIP/2.0 183 Session Progress.
Via: SIP/2.0/TCP
137.208.90.164:56136;branch=z9hG4bK-d87543-a107a77a6311422d-1--d87543-;rport=3099.
From: "Alexander Bergolth"<sip:30001 at wu-wien.ac.at>;tag=5b6d7b31.
To: "996050"<sip:996050 at wu-wien.ac.at>;tag=as2e40807f.
Call-ID: MTVjYzlhMDdjMjAwODExZDEyNzk5M2IwN2UxNjhlYTc..
CSeq: 2 INVITE.
User-Agent: Asterisk PBX.
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.
Supported: replaces.
Contact: <sip:996050 at 137.208.89.135>.
Content-Type: application/sdp.
Content-Length: 283.
.
v=0.
o=root 6978 6978 IN IP4 137.208.89.135.
s=session.
c=IN IP4 137.208.89.65.
t=0 0.
m=audio 35064 RTP/AVP 0 8 101.
a=rtpmap:0 PCMU/8000.
a=rtpmap:8 PCMA/8000.
a=rtpmap:101 telephone-event/8000.
a=fmtp:101 0-16.
a=silenceSupp:off - - - -.
a=ptime:20.
a=sendrecv.
a=nortpproxy:yes.
-------------------- 8< --------------------

-------------------- 8< --------------------
15:57:35.814136 IP 137.208.90.164.3099 > 137.208.89.45.5060: P
4236850032:4236851080(1048) ack 224540451 win 64256
15:57:35.814147 IP 137.208.89.45.5060 > 137.208.90.164.3099: . ack 1048
win 2003
15:57:35.814351 IP 137.208.89.45.5060 > 137.208.90.164.3099: P
1:550(549) ack 1048 win 2003
15:57:35.814430 IP 137.208.89.45.5060 > 137.208.90.164.3099: P
550:1264(714) ack 1048 win 2003
15:57:35.814850 IP 137.208.90.164.3099 > 137.208.89.45.5060: . ack 1264
win 64177
15:57:35.915829 IP 137.208.90.164.3099 > 137.208.89.45.5060: P
1048:1418(370) ack 1264 win 64177
15:57:35.955948 IP 137.208.89.45.5060 > 137.208.90.164.3099: . ack 1418
win 2003
15:57:36.017309 IP 137.208.90.164.3099 > 137.208.89.45.5060: P
1418:2672(1254) ack 1264 win 64177
15:57:36.017320 IP 137.208.89.45.5060 > 137.208.90.164.3099: . ack 2672
win 2003
15:57:36.017397 IP 137.208.89.45.5060 > 137.208.90.164.3099: P
1264:1813(549) ack 2672 win 2003
15:57:36.018604 IP 137.208.89.45.5060 > 137.208.90.164.3099: P
1813:2388(575) ack 2672 win 2003
15:57:36.019170 IP 137.208.90.164.3099 > 137.208.89.45.5060: . ack 2388
win 64256
15:57:36.041454 IP 137.208.89.45.35064 > 137.208.90.164.10676: UDP,
length 172
15:57:36.041537 IP 137.208.89.45.5060 > 137.208.90.164.3099: P
2388:3200(812) ack 2672 win 2003
15:57:36.046899 IP 137.208.90.164.10677 > 137.208.89.65.35065: UDP,
length 132
15:57:36.061155 IP 137.208.89.45.35064 > 137.208.90.164.10676: UDP,
length 172
15:57:36.080128 IP 137.208.90.164.10676 > 137.208.89.65.35064: UDP,
length 172
15:57:36.081157 IP 137.208.89.45.35064 > 137.208.90.164.10676: UDP,
length 172
[...]
-------------------- 8< --------------------

Thanks in advance,
--leo

P.S.: I'm using openser-1.2 and rtpproxy-cvs20070222.

-- 
e-mail   ::: Alexander.Bergolth (at) wu-wien.ac.at
fax      ::: +43-1-31336-906050
location ::: Computer Center | Vienna University of Economics | Austria