[SR-Users] SIP Security handling in Kamailio IMS

[Daniel-Constantin Mierla]

Hello,

On 30.06.20 00:21, BALL SUN wrote:
> Hi
>
> During the testing with Kamailio IMS, we found that SUBSCRIBE and
> NOTIFY message flow between UE and P-CSCF is shown below.
>
> SUBSCRIBE and its response: 192.168.1.102:9101 (port-c) ->
> 192.168.2.66:6101 (port-s)
> NOTIFY: 192.168.2.66:5101 (port-c) -> 192.168.1.102:9100 (port-s)
>
> based on the sip security, is it the expected behavior that they are
> using port-c and port-s?
>
> The reason why we asked is because we found that the NOTIFY did not
> properly propagate to the UE due to different port addresses.
>
> Does anyone have this experience? and how we can resolve it?

Not sure what you refer with port-c and port-s, but in kamailio you have
the option to enforce the local socket for sending the sip messages out.
See the force_send_socket(), set_send_socket() or $fs variable.

Usually, the NOTIFY should be sent from the socket where the SUBSCRIBE
was received.

However, not that in case of TCP/TLS, the connections may use ephemeral
ports, being different that the socket Kamailio is listening on.

Cheers,
Daniel

-- 
Daniel-Constantin Mierla -- www.asipto.com
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