Hello I have my servers behind a NAT, with servers that make a call with bypass media / direct media all works fine. But when my media servers need to process audio I'm having issues. Looking at the SDP my local IP of the server is in there. I changed my config to add the nethelper.so and add the below: # ----- NAT Helper ----- #!ifdef WITH_NAT #modparam("nathelper", "rtpproxy_sock", "udp:127.0.0.1:7722") modparam("nathelper", "natping_interval", 30) modparam("nathelper", "ping_nated_only", 1) #modparam("nathelper", "sipping_bflag", 7) #modparam("nathelper", "sipping_from", "sip:pinger@kamailio.org") #modparam("registrar|nathelper", "received_avp", "$avp(i:80)") #modparam("usrloc", "nat_bflag", 6) #!endif In my route I added: if (search("User-Agent: FS Box") {fix_nated_sdp("3");};