[Serusers] How to check if callee is behind NAT ?

[Jan Janak]

On 12-05 11:43, jimmy huang wrote:
> Hi  all,
> now i can configure SER to check if caller is behind NAT , and modified SDP . forece using rtpproxy ,
>  so client can successed make voice call through NAT/Firewall
> 
> but if caller is in public network , and callee is behind NAT ,
> how to check if calee is behind NAT , and modify SDP , also force caller and callee to use rtpproxy 
> in ser.cfg ??

  You can detect that when the callee is registering (from the REGISTER
  message and store it in the user location database as a flag). Later,
  when you do lookup("location") the flag will be restored by registrar
  and you can test the flag to see if the calee is behind NAT or not.
  See sip_router/etc/nathelper.cfg -- this file is using this approach.

    Jan.