[SR-Users] Difficulties with with loose_route() when trying to handle non-compliant ACK

[Andrew Pogrebennyk]

Richard,

well, the RURI of remote ACK has proxy IP address 10.200.70.100 so proxy
thinks that previous hop was a strict router. I can't think of any
workaround that would not be an ugly hack at the moment, though.

On 11/23/2012 03:24 AM, Richard Brady wrote:
> Hi guys
> 
> I have a multihomed Kamailio proxy sitting between two B2BUAs on
> separate networks and record-routing all dialogs.
> 
> The problem I have is that when one of these devices receives a 200
> OK, it does not populate the RURI of the ACK correctly. Instead of
> taking it from the Contact header on the 200 OK, it uses the user part
> from the Contact header and sets the domain to the proxy IP. It then
> also populates the Route headers.
> 
> The ACKs are below and the IPs are:
> 
> 10.152.1.92:5060: UAC on outside
> 10.200.70.100:5060: proxy outside interface
> 192.168.242.100: proxy inside interface
> 192.168.242.102: UAS on inside
> 
> This the ACK message going into and coming out of the proxy.
> 
> # U 10.152.1.92:5060 -> 10.200.70.100:5060
> ACK sip:natted_ua*9197**192.168.242.102*5080*udp at 10.200.70.100 SIP/2.0.
> Via: SIP/2.0/UDP 127.0.1.1:5060;branch=z9hG4bK-2280-1-5.
> Route:  <sip:10.200.70.100;r2=on;lr=on;nat=yes>,<sip:192.168.242.100;r2=on;lr=on;nat=yes>.
> From: sipp <sip:sipp at 127.0.1.1:5060>;tag=2280SIPpTag001.
> To: sut <sip:9197 at 10.200.70.100:5060>;tag=p0FaeQ1QUS9ae.
> Call-ID: 1-2280 at 127.0.1.1.
> CSeq: 1 ACK.
> Contact: sip:sipp at 127.0.1.1:5060.
> Max-Forwards: 70.
> Subject: Performance Test.
> Content-Length: 0.
> .
> 
> # U 10.200.70.100:5060 -> 192.168.242.100:5060
> ACK sip:192.168.242.100;r2=on;lr=on;nat=yes SIP/2.0.
> Via: SIP/2.0/UDP 10.200.70.100;branch=z9hG4bKcydzigwkX.
> Via: SIP/2.0/UDP
> 127.0.1.1:5060;rport=5060;received=10.152.1.92;branch=z9hG4bK-2280-1-5.
> Route:  .
> From: sipp <sip:sipp at 127.0.1.1:5060>;tag=2280SIPpTag001.
> To: sut <sip:9197 at 10.200.70.100:5060>;tag=p0FaeQ1QUS9ae.
> Call-ID: 1-2280 at 127.0.1.1.
> CSeq: 1 ACK.
> Contact: <sip:sipp at 127.0.1.1:5060;alias=10.152.1.92~5060~1>.
> Max-Forwards: 69.
> Subject: Performance Test.
> Content-Length: 0.
> 
> So I am trying to understand why it is trying to relay to itself (I
> have mhomed=1) and why it is rewriting the RURI as if it is a strict
> router.
> 
> Currently decode_contact() is disabled but enabling doesn't seem to
> help. Unless there is a very specific place where it belongs.
> 
> Any advice would be hugely appreciated. I can always paste logs /
> configs / traces.
> 
> Richard
> 
> --
> Richard Brady
> M: +44 (0)7771 623 348
> T:  +44 (0)20 8144 8160
> E: rnbrady at gmail.com
> 
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