My Kamailio box works very well for a year, in front of a Freeswitch box. Nowadays, some of my users live problems about receiving calls. But this problem occurs on a couple of specific users. %1 of users complain about it. When I capture the traffic, I see that, Kamailio receives an invite package from freeswitch but takes no action. Normally it should response with a 100 trying message. Here is the INVITE package. 1.2.3.6 is the Freeswitch box and 1.2.3.2 is the Kamailio box. I captured this package on Kamailio box.
Via: SIP/2.0/UDP 1.2.3.6;rport;branch=z9hG4bKZU1Z76FvDZ26r.
Route: <sip:1.2.3.2>;lr.
Max-Forwards: 65.
Call-ID: 72b344f4-1c09-1233-ad8d-0050568e9066.
CSeq: 70585075 INVITE.
User-Agent: FreeSWITCH-mod_sofia/1.4.14+git~20141119T221113Z~ca1d990cfc~64bit.
Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, INFO, UPDATE, REGISTER, REFER, NOTIFY, PUBLISH, SUBSCRIBE.
Supported: timer, path, replaces.
Allow-Events: talk, hold, conference, presence, as-feature-event, dialog, line-seize, call-info, sla, include-session-description, presence.winfo, message-summary, refer.
Content-Type: application/sdp.
Content-Disposition: session.
Content-Length: 270.
X-AUTH-IP: 159.253.40.138.
X-BF-SRC: 2.
X-FS-Support: update_display,send_info.
.
v=0.
o=FreeSWITCH 1421813895 1421813896 IN IP4 1.2.3.6.
s=FreeSWITCH.
c=IN IP4 1.2.3.6.
t=0 0.
m=audio 28384 RTP/AVP 3 8 0 101 13.
a=rtpmap:3 GSM/8000.
a=rtpmap:8 PCMA/8000.
a=rtpmap:0 PCMU/8000.
a=rtpmap:101 telephone-event/8000.
a=fmtp:101 0-16.
a=ptime:20.
I use standart location lookup and relay procedure in Kamailio default script.
Is there anything wrong with this INVITE package and how can I trace this issue on Kamailio box?
Thank you.