I am using kamailio with rtp proxy module.  I have 2 questions /issues .

1. When caller or callee ends the call the other end call is not disocnnecting .

UA is pjsip based and behind  NAT router. Present  call flow is 

pjsipUA (LAN_ip)----->Router (Publicip)-------->Kamailio_with_RTP proxy----> ThridParty SIP Server 

UA local ip : 192.168.2.11

UA public IP : 89.78.92.23

Kamailio Public ip: 94.50.203.32

Third party Sip server : 76.42.89.25

Here When I disconnect call from either  side , it is not disconnecting other side .

2. My second requirement is , how can I define port of third party server .

for example if have 3 or 4 sip servers with different sip registration ports other tahn 5060 

How can I route registration requests coming from UAs to different ports of third party servers.

Please bear my ignorance I am new to kamailio .Hope some experts will help me here .

Attached kamailio config and SIP trace taken from kamailio server 

Thank you