Hello, This was originally posted for opensips, but I figured someone here might know the answer as well since kamailio and opensips are "alike". I have the following RTPproxy configuration: modparam("nathelper", "rtpproxy_sock", "1 == udp:127.0.0.1:12221") modparam("nathelper", "rtpproxy_sock", "2 == udp:127.0.0.1:12222") In the main route I decide which instance to select for each INVITE containing SDP: if($ru=~"1.1.1.10") { set_rtp_proxy_set("1"); xlog("L_INFO", "USE RTP PROXY 01 \r\n"); } else if($ru=~"2.2.2.10") { set_rtp_proxy_set("2"); xlog("L_INFO", "USE RTP PROXY 02 \r\n"); } else { t_reply("404", "Not Found"); exit; } rtpproxy_offer(); I’m getting the following error for a 200 OK: ERROR:nathelper:select_rtpp_node: script error -no valid set selected ERROR:nathelper:force_rtp_proxy_body: no available proxies Do I need to do the same decision for 200 OK messages, and call rtpproxy_answer()? Regards, Grant