Kamailio - Asterisk integration - sr-users

27 Sep 2018

Hello guys,

I'm following this guide: 
https://kb.asipto.com/asterisk:realtime:kamailio-4.0.x-asterisk-11.3.0-astdb

And I have the following schema:

 Phone A   ----->   Kamailio    ----->    Asterisk    ----->   Phone B 
(10.0.8.249)        (10.0.6.123)            (10.0.3.144) (10.0.13.23)

I think the flow it is like (because when UAC register to Asterisk, the 
contact points to Kamailio IP): 

1. Phone A --> Kamailio --> Asterisk 
2. Asterisk --> Kamailio --> Phone B

In attachment is the pcap of the call, kamailio config.

The problem is that I never receive ACK after 200 OK and call drops after 
30 seconds?

Kamailio version 5.1 and Asterisk version 15.1

Phones are grandstreams and also tested with microsip soft client and same 
results... Like "Phone A" never sends ACK back

I tried different approaches to change contact header in 200 OK, because 
is Asterisk IP. Disable NAT  handling. Different "nat_uac_test" flags, but 
still without success :(

Also tried with this NAT detection and manage routes (again without any 
success) - source 
https://github.com/sipwise/kamailio/blob/master/etc/kamailio.cfg

# Caller NAT detection
route[NATDETECT] {
#!ifdef WITH_NAT
        force_rport();
        if (nat_uac_test("19")) {
                if (is_method("REGISTER")) {
                        fix_nated_register();
                } else {
                        if(is_first_hop()) {
                                set_contact_alias();
                        }
                }
                setflag(FLT_NATS);
        }
#!endif
        return;
}

# RTPProxy control and signaling updates for NAT traversal
route[NATMANAGE] {
#!ifdef WITH_NAT
        if (is_request()) {
                if(has_totag()) {
                        if(check_route_param("nat=yes")) {
                                setbflag(FLB_NATB);
                        }
                }
        }
        if (!(isflagset(FLT_NATS) || isbflagset(FLB_NATB))) return;

        if(nat_uac_test("8")) {
                rtpproxy_manage("co");
        } else {
                rtpproxy_manage("cor");
        }

        if (is_request()) {
                if (!has_totag()) {
                        if(t_is_branch_route()) {
                                add_rr_param(";nat=yes");
                        }
                }
        }
        if (is_reply()) {
                if(isbflagset(FLB_NATB)) {
                        if(is_first_hop())
                                set_contact_alias();
                }
        }
#!endif
        return;
}

Thanks in advance

Denislav Raychev Tsonev  |  Integration and Infrastructure Engineer |  
Musala Soft JSC 
www.musala.com  |  t: +359 2 969 58 21   |  m: +359 878 270 965   |  f: 
+359 2 969 58 22 
World Trade Center, 36 Dragan Tsankov blvd., Sofia 1057, Bulgaria 