Asterisk-kamailio issue

Hello All,

I’m using Kamailio as a Border controller for my VoIP Research project at my school.
The problem I’m facing is Kamailio routes the traffic to the private network where my asterisk machine is listening.
The asterisk machine responds to the Kamailio using the public network but not the private. Is this an issue with Asterisk? If so how do I resolve it?

  client	kam_public    Kam_pvt      Ast_pvt    Ast_public
|			|		|		|		|
|			|		|		|		|
|    INVITE		|		|		|		|
|---------------->|		|    INVITE	|		|
|			|		|---------->|		|
|			|		|		|		|
|			|		|		|		|
|			|		|		|		|
|			|		|     404	|		|
|			|<----------|-----------|------------|
|			|		|		|		|
|			|		|     ACK	|		|
|			|		|---------->|		|
|			|		|		|		|
|     404		|		|		|		|
|<----------------|		|		|		|
|			|		|		|		|
|     ACK		|		|		|		|
|---------------->|		|		|		|
|			|		|		|		|
|			|		|		|		|

Regards
Gnaneshwar