Hello, I have setup openser (1.1.1-tls) to talk to our UA's on port 5060 and some UA's on port 4800 (as provider blocks 5060). I am using Mediaproxy (1.9.0). Currently the following works: 1. UA using 5060 makes call to UA using 4800: Phone bell rings and audio two way no issues. 2. UA using 4800 makes call to UA using 5060. Phone bell rings but no audio in either direction All UA's use RTP port 5004. What can I add to the following loose route section so that I can make "2" work above. My loose route section in openser is: ##################################################### listen= udp:XXX.XXX.XXX.XXX:5060 listen= udp:XXX.XXX.XXX.XXX:4800 # Loose route section if (loose_route()) { if ((method=="INVITE" || method=="REFER") && !has_totag()) {(20) sl_send_reply("403", "Forbidden"); break; }; if (method=="INVITE") { (21)if (!proxy_authorize("","subscriber")) { proxy_challenge("","0"); break; } else if (!check_from()) { sl_send_reply("403", "Use From=ID"); break; }; consume_credentials(); if (client_nat_test("3") || search ("^Route:.*;nat=yes")) { setflag(6); use_media_proxy(); }; }; route(1); break; }; ##################################################### Please do provide if there is a solution to this issue. Your inputs appreciated. regards, Roger