Hi All, I am trying to set up SER with Dispatcher to loadbalancing the traffic to 2 * boxes. SER was able to select the * IPs from the dispatcher.list, but * SIP response back authentication required. It work perfectly if I i use rewritehostport instead of using the dispatch module. I am pulling my hair now and still don't know where the problem at. openser.cfg if (uri=~"sip:\+?[1-9][0-9]*@.*") { ds_select_dst("2", "0"); route(4); route(5); return; }; route[4] { if (isflagset(6)) { force_rport(); fix_nated_contact(); force_rtp_proxy(); }; } route[5] { setflag(1); t_on_reply("1"); forward(uri:host, uri:port); append_hf("P-hint: main PSTN route\r\n"); t_on_failure("1"); if (!t_relay()) { sl_reply_error(); return; }; } onreply_route[1] { if (isflagset(6) && status=~"(180)|(183)|2[0-9][0-9]") { if (!search("^Content-Length:[ ]*0")) { force_rtp_proxy(); }; }; if (nat_uac_test("1")) { fix_nated_contact(); }; } failure_route[1] { append_hf("P-hint: backup PSTN route\r\n"); rewritehost("x.x.x.x"); rewriteport( "5060"); append_branch(); t_relay(); } SIP.conf form * [general] host=dynamic bindaddr=0.0.0.0 port=5060 useragent=x context=default disallow=all allow=g729 allow=ulaw autocreatepeer=yes dtmfmode=rfc2833 qualify=no nat=yes canreinvite=no Retransmitting #5 (no NAT): SIP/2.0 407 Proxy Authentication Required Via: SIP/2.0/UDP x.x.x.x;branch=0 Via: SIP/2.0/UDP 192.168.1.107:5060;received=x.x.x.x;branch=z9hG4bK263724 From: "testing" <sip:testing@64.127.123.100 >;tag=5318 To: < sip:exten@x.x.x.x>;tag=as1cf1692c Call-ID: 1141227578-724-TF-GIXXER(a)192.168.1.107 CSeq: 813 INVITE User-Agent: x Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER Contact: < sip:exten@x.x.x.x> Proxy-Authenticate: Digest realm="asterisk", nonce="40a9764f" Content-Length: 0