Kamailio Blind Call Forwarding - sr-users

18 Apr 2016


      Hi all,
I'm trying to make a blind call forward to "1002" if a UA calls "1" into Kamailio. At the moment I have the following config:
if ( $rU=~"^[1]$" && src_ip==$sel(cfg_get.pstn.gw_ip) ) {
                               sl_send_reply("181", "Redirecting");
                               $ru = "sip:1002@" + $sel(cfg_get.pstn.gw_ip) + ":" + $sel(cfg_get.pstn.gw_port) + ";user=phone";
                               force_send_socket(udp:MY_EXTERN_IP:5060);
                               route(NORMAL_RELAY); #Just t_on_branch/reply/failure
                               if (!t_relay()) {
                                               sl_reply_error();
                               }
                               exit;
                }
The calling UA is from the PSTN as well as the called UA. Problem right now is that the PSTN's anti-Loop protection jumps in and rejects the INVITE to 1002.
Question: Is it possible to tell the calling UA "Hey wait, 181..." with Kamailio, then build seperately an independent Call Leg (with new CallID?) from Kamailio to UA "1002" and finally to put them together?
Any help is very much appreciated even if they are just guides/examples. I'm using Kamailio 4.3.5 on CentOS 7.2.
Very Respectfully
Dimitry Nagorny
Trainee