[OpenSIPS-Devel] How to make OpenSIPS reuse client's TCP/TLS connection (and not try to connect on its own)?

[Klaus Darilion]

Actually your client announces port 5061 in the Contact header. Either 
the client should announce the port of the ephemeral or perform NAT 
traversal at the proxy, e.g. fix_nated_contact()

If the SUBSCRIBE processing happens on the same proxy which does the NAt 
traversal there may be an issue - presence module would need some kind 
of "received_avp" feature (like registrar module) - I do not know if 
this is supported yet.

regards
klaus

Ivan Genov schrieb:
> Hi Bogdan,
>  
> Thanks for the answer.  I now realize I have not provided all relevant 
> information and I have not been fully correct with my first message.
>  
> I have to mention that I have a custom module on the server, which takes 
> care of subscriptions for one custom event. This module is workign fine 
> and it is responsible for sending NOTIFYs when needed.
>  
> I am pasting three packets of the communication between the client and 
> the server below. The client sends SUBSCRBE through the TLS connection 
> and the server responds with 202 OK to the client using the same (single 
> at that time) TLS connection which came from the client. But after that, 
> when the server (my custom module) needs to send NOTIFY to the client, 
> for some reason the server establishes a new TLS connection to the 
> client through which it sends the NOTIFY. Here are the packets:
>  
> -----------------------------------------------------------------
> SUBSCRIBE sips:ivan at 10.0.5.5 SIP/2.0
> Via: SIP/2.0/tls 
> 10.0.5.112:2013;rport;branch=z9hG4bKPj6a7bed4a838c416fa70d57c85ef98e21
> Max-Forwards: 70
> From: "Ivan" <sips:ivan at 10.0.5.112>;tag=8e8c2497ec8e4edeb3fc031ad861698d
> To: sips:ivan at 10.0.5.5
> Contact: "Ivan" <sips:ivan at 10.0.5.112:5061;transport=TLS>
> Call-ID: 41d9d9772e89462ca9e71e225d03f596
> CSeq: 18467 SUBSCRIBE
> Event: custom-event
> Expires: 120
> Accept: text/plain
> Allow-Events: presence, refer, custom-event
> Content-Type: text/plain
> Content-Length: 6
>  
> 010203
> -----------------------------------------------------------------
> SIP/2.0 202 OK
> Via: SIP/2.0/tls 
> 10.0.5.112:2013;rport=2013;branch=z9hG4bKPj6a7bed4a838c416fa70d57c85ef98e21
> From: "Ivan" <sips:ivan at 10.0.5.112>;tag=8e8c2497ec8e4edeb3fc031ad861698d
> To: sips:ivan at 10.0.5.5;tag=10.0.1219249054.4
> Call-ID: 41d9d9772e89462ca9e71e225d03f596
> CSeq: 18467 SUBSCRIBE
> Expires: 120
> Server: OpenSER (1.3.0-tls (i386/linux))
> Content-Length: 0
> -----------------------------------------------------------------
> NOTIFY sips:ivan at 10.0.5.112:5061;transport=TLS SIP/2.0
> Via: SIP/2.0/TLS 10.0.5.5:5061;branch=z9hG4bKc2bf.75041b55.0
> To: sip:ivan at 10.0.5.112;tag=8e8c2497ec8e4edeb3fc031ad861698d
> From: sip:ivan at 10.0.5.5;tag=10.0.1219249054.4
> CSeq: 1 NOTIFY
> Call-ID: 41d9d9772e89462ca9e71e225d03f596
> Content-Length: 6
> User-Agent: OpenSER (1.3.0-tls (i386/linux))
> Max-Forwards: 70
> Event: custom-event
> Subscription-State: active;expires=120
> Content-Type: text/plain
>  
> 010203
> -----------------------------------------------------------------
>  
> Can it be told from these packets what makes the server think the 
> connection point is different? I suspect the connection point looks 
> different to the server because 
> "sips:ivan at 10.0.5.112:5061;transport=TLS" is different SIP URI than 
> "sips:ivan at 10.0.5.5", maybe? 10.0.5.112 is the client's IP and 10.0.5.5 
> is the server's.
>  
>  
> Thanks in advance,
>  
> Ivan.
>  
>  
> ----- Original Message ----
> From: Bogdan-Andrei Iancu <bogdan at voice-system.ro>
> To: Ivan Genov <ivangg_q at yahoo.com>
> Cc: devel at lists.opensips.org
> Sent: Wednesday, August 20, 2008 1:20:20 AM
> Subject: Re: [OpenSIPS-Devel] How to make OpenSIPS reuse client's 
> TCP/TLS connection (and not try to connect on its own)?
> 
> Hi Ivan,
> 
> The OpenSIPS reuses the TCP/TLS connection only if the connection point
> (where it tries to connect to) is already involved in a established
> connection.
> 
> In your case, maybe the connection point looks different than any
> existing connections, so a new one is opened.
> 
> Regards,
> Bogdan
> 
> Ivan Genov wrote:
>  > Hi,
>  > 
>  > I am noticing that when a client connects to the OpenSIPS server via
>  > TLS the server is establishing a new TLS connection to the client and
>  > sends the respond through it. This works OK for internal LAN, but if
>  > you are trying to connect with the client from outside Internet (or
>  > other unreachable for the OpenSIPS place) the OpenSIPS cannot
>  > establish this connection and it will not work.
>  > 
>  > My expectation was that the SIP server would reuse the same TCP/TLS
>  > connection that the client made to it, but obviously it is not so. Do
>  > you know if there is a way to configure the server (possibly the
>  > client), so that the server reuses the client's connection and does
>  > not try to create a new one?
>  > 
>  > 
>  > Thanks,
>  > 
>  > Ivan.
>  >
>  > ------------------------------------------------------------------------
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