Yeah sure, attached here is the trace from the CISCO logs. Not in pcap format.
Also this is the flow of the call.

                                                       
  +-----------+               +--------------+         +------------------+    
  |Provider |+--------> +Kamailio  +------>+CISCO IAD  |    
  +-----------+               +--------------+          +-----------------+    
                                         |    ^                         
                                         v    |                         
                                    +-----------+                     
                                    |Asterisk |                     
                                    +-----------+                     

Thanks and best Regards,
                                                       
--

On Tue, May 12, 2015 at 11:50 AM, Alex Balashov <abalashov@evaristesys.com> wrote:
Is the UAC in this case a 2543 endpoint by chance? Can you send a complete SIP trace of the entire setup?

--
Alex Balashov | Principal | Evariste Systems LLC
303 Perimeter Center North, Suite 300
Atlanta, GA 30346
United States

Tel: +1-800-250-5920 (toll-free) / +1-678-954-0671 (direct)
Web: http://www.evaristesys.com/, http://www.csrpswitch.com/

Sent from my BlackBerry.
From: SamyGo
Sent: Tuesday, May 12, 2015 11:46
To: SIP Router - Kamailio (OpenSER) and SIP Express Router (SER) - Users Mailing List
Reply To: Kamailio (SER) - Users Mailing List
Subject: [SR-Users] Multi-homed Kamailio Modifies ACK

Hi all,

I'm having a scenario where I'm sending call to CISCO IAD2431. The call establishes with 200OK from CISCO and Kamailio sends back modified ACK. Cisco at this points gives out an error and sends 200OK again, Kamailio replies with ACK, and this cycle goes on until the call drops.

Here is the error from CISCO:

Failed FROM/TO Request check
  old_from: "Test Phone" <sip:+14432232221@192.168.1.106>;tag=as370915fc
  old_to:   <sip:+14444812211@sip.iamip.com:5041>;tag=9FEC572E-100F
  new_from: "Test Phone" <sip:+14432232221@192.168.1.106>;tag=as370915fc
  new_to:   <sip:+14444812211@192.168.1.244:5041>;tag=9FE

I've 
#auto_aliases=no

and,
listen=udp:44.33.22.11:5041 
listen=udp:192.168.1.244:5041 

Kamailio sends INVITE through the Public IP to the CISCO gw, but decides to change the ACK header.

Any advise please.

Best Regards,
Sammy.



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