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.