I am new to kamailio. As my requirement is to forward all client register message to server1 for registration( basically , client can register with kamailio ( optional) , and with server 1 ( MUST )), and other SIP request like INVITE, need to be forward to server 2. 

Client  -----  kamailio --register--- server1

                      (invite)\                   /

                                       Server2

So, everytime client can do registration with server 1 and while making calls it should route to server 2 which ultimate forwrd to server 1.

Tried to change kamailio config file, but only inite message forwarded not others.

Can anyone please guide me, how to proceed ?

Thanks in advance,