[SR-Users] Source Port on TLS OPTIONS from Dispatcher

[Charles Phillips]

Thanks for the quick response Joel.  Yes, I have read the article and I have tested and confirmed that I am correctly appending the contact header (I probably should have left that in the snippet for clarity).  Below is an example of Kamailio setting up the connection.  It is going out port 46245 this time, but it is random.

07:59:23.572319 IP *my.kamailio.server*.46245 > *ms.teams.server*.sip-tls: Flags [P.], seq 1:518, ack 1, win 502, length 517
07:59:23.802458 IP *ms.teams.server*.sip-tls > *my.kamailio.server*.46245: Flags [P.], seq 1:3767, ack 518, win 2051, length 3766

The TLS connection shows as successful in the logs.


- Charles 


Date: Thu, 7 Jan 2021 19:12:10 -0800
From: Joel Serrano <joel at textplus.com <mailto:joel at textplus.com>>
To: "Kamailio (SER) - Users Mailing List"
	<sr-users at lists.kamailio.org <mailto:sr-users at lists.kamailio.org>>
Subject: Re: [SR-Users] Source Port on TLS OPTIONS from Dispatcher
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	<CAMtXxQnLtEyD=40cwKembxiyj3D778eK=+5JD7sL4CvYbYXF1g at mail.gmail.com <mailto:CAMtXxQnLtEyD=40cwKembxiyj3D778eK=+5JD7sL4CvYbYXF1g at mail.gmail.com>>
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Hi Charles,

I don't think your issue is rport, make sure you are setting the Contact
header correctly.

Have you checked this blog post:
https://skalatan.de/en/blog/kamailio-sbc-teams <https://skalatan.de/en/blog/kamailio-sbc-teams> ?

There is a specific section that talks about how to tell Kamailio to send
the OPTIONS like MS Teams wants them.

Good luck,
Joel.


> On Jan 7, 2021, at 7:31 PM, Charles Phillips <charles at rustybike.com> wrote:
> 
> Hello all.  As they say in radio, “long time listener, first time caller”
> 
> Anyway, I am having trouble getting past the following road block and any help would be greatly appreciated.
> 
> Kamailio version is 5.4.3 
> 
> When attempting to use dispatcher to send OPTIONS packets to several TLS destinations, the packets are leaving the Kamailio server on random ports.  This is a problem because the servers I am sending the OPTIONS to (MS Teams) are enforcing rport so the responses are returned to a port that Kamailio is not listening on.  I have tried to force the socket in the event route (relevant parts of snippet below) but it does not appear to help.  I should also mention that I am not behind NAT and the TLS socket is specified in the dispatcher attrs. 
> 
> event_route[tm:local-request] {
>     sip_trace();
> 
> 
>     $fs = “tls:**ip-address**:5061”;
> 
> 
> }
> 
> I have used Kamailio as a TLS server for many projects, but this is my first time as a client.  I am sure I am missing something.
> 
> - Charles
> 
> 
> 
> 

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