Hi All, Kamailio send 2 INVITE(lookup rewrite r-uri and append branch) request for Client behind NAT. Due to this reason for one request,Client respond with 486 Busy here. we only want to send  1 INVITE request. Following are the AOR for client at kamailio.if field(ip port) in CONTACT and RECEIVED differ then kamailio send 2 INVITE request. FOLLOWING INVITE HAS BEEN GENERATED AFTER LOOKUP FUNCTION(one from contact and one from Received field). INVITE:sip:123@192.168.230.124:45672 <http://INVITE:sip:123@192.168.230.124:45672> INVITE:sip:123@204.192.206.208:45672 <http://INVITE:sip:123@204.192.206.208:45672> I want only ONE INVITE request to be generated.Please suggest how do solve this issue or if there is any config change or any code change required to achieve this?   AOR:: 123                 Contact:: sip:123@192.168.230.124:45672 <http://sip:123@192.168.230.124:45672> Q=1                         Expires:: 894                         Callid:: 003A8EC4-12351(a)192.168.230.124 <mailto:003A8EC4-12351@192.168.230.124>                         Cseq:: 2                         User-agent:: SIPPER for 3CX Phone                         Received:: sip:204.192.206.208 <http://204.192.206.208>: 45672                         State:: CS_NEW                         Flags:: 0                         Cflag:: 192                         Socket:: udp:172.12.120.88:5060 <http://172.12.120.88:5060>                         Methods:: 4294967295                         Ruid:: uloc-5aba112d-7fce-5                         Reg-Id:: 0                         Last-Keepalive:: 1522144583                         Last-Modified:: 1522144583 thanks, amit _______________________________________________ Kamailio (SER) - Users Mailing List sr-users(a)lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users