I want to use kamailio as a forwarding proxy infront of SIP registrar like asterisk/freeswitch without any rtpproxy to reduce the load on server and to be able to handle more requests .  I am using default kamailio config file  registration is working fine but call is not connecting .  So sip clients should register on asterisk(or freeswitch)   and  able to receive inbound calls  too .

I am interested in only REGISTER & INVITE messages to restrict the messages based on sipclient's source ip .   Please can someone help me with a working configuration for this setup .

This is the topology ..

(Sipclients with or without NAT ) ---------> (Kamailio without rtpproxy)-------------->(Asterisk or freeswitch or anyother sipserver  )