Hello again,
I am not a SIP expert, and I’m new to Kamailio, really enjoying learning it, but I’ve hit
a blocker and I’m pretty sure I’ve missed something really simple.
I’m looking to implement the Redirect Server from here:
https://tools.ietf.org/html/rfc3665#section-3.6
<https://tools.ietf.org/html/rfc3665#section-3.6> (the Avaya Session Manager being
Alice), Kamailio as the Redirect Server. My configuration is working fine, and I can see
the 302 going back (to Avaya SM), I then get the ACK I’m expecting.
The incoming SIP request contains a number of fields, including a Contact header, which
I’m told SM needs on the return. But the send_reply() or sl_send_reply() doesn’t return
the Contact header, and I am unable to manually set it, or any other header, using any of
the append_hf(), append_to_reply() etc. mechanisms. I’m executing a msg_apply_changes()
which succeeds, but no Contact header is returned.
I’ve tried an sl_send_reply(“100”, “Trying”) before any other processing, and Wireshark
confirms that the SIP response is basically identical to the 302 response sent after
processing… The goal is to run this stateless, I’m assuming this is possible - it
certainly feels like it should be.
I’ve re-read the intros & tutorials, and other reading material such as this
http://kamailio.org/docs/ser-getting-started/SER-GettingStarted.pdf
<http://kamailio.org/docs/ser-getting-started/SER-GettingStarted.pdf> but, this,
even my best Google-fu has left me utterly stumped…
The sl_send_reply documentation
https://kamailio.org/docs/modules/5.2.x/modules/sl.html#sl_send_reply
<https://kamailio.org/docs/modules/5.2.x/modules/sl.html#sl_send_reply> states “If
the code is in the range 300-399 (redirect reply), the current destination set is appended
to the reply as Contact headers” but the Contact header is definitely not being set when I
use this.
Apologies in advance if eyes are rolling and this is really obvious, or (and?) that my
lack of SIP knowledge is shining through - any tips or guidance would be appreciated. I
certainly feel overwhelmed by the number of modules and the interplay between them.
If the answers to this, and other things along these lines are contained in the admin
book, that’s fab, I’ve just filled the form out :)
Cheers - Robert...