Hi!! We work with ser 0.8.14, and mediaproxy. As clients we are using two Windows Messenger 4.7 in two different ADSL (NATed) lines connecting to SER in a public Internet address. The scenario is as follows: The sip server is listening on 194.179.25.55. The user chano@ wmserver.hi.inet on the machine sayuritra (private address: 172.26.0.52, public address: 217.125.212.22) calls to the user raquel(a)wmserver.hi.inet on hobbes (private address: 192.168.1.34, public addess: 80.32.97.245). The messages captured in the sip server are the following: U 217.125.212.22:10094 -> 194.179.25.55:5060 INVITE sip:raquel@wmserver.hi.inet SIP/2.0..Via: SIP/2.0/UDP 172.26.0.52:13552.. From: "chano" <sip:chano@wmserver.hi.inet>;tag=181d13b4-e1f 0-4dbd-9606-18e52b57dbf6..To: <sip:raquel@wmserver.hi.inet>. .Call-ID: ab9bb0f1-3a43-4ecd-a787-03a439714bda@172.26.0.52..CSeq: 1 INVITE.. Contact: <sip:172.26.0.52:13552>..User-Agent: Windows RTC/1.0..Content-Type: application/sdp.. Content-Length: 529....v=0..o=sayuritra 0 0 IN I P4 172.26.0.52..s=session..c=IN IP4 172.26.0.52..b=CT:1000..t=0 0.. m=audio 38370 RTP/AVP 97 111 112 6 0 8 4 5 3 101..a=rtpmap:97 red/8000.. a=rtpmap:111 SIREN/16000..a=fmtp:111 bitrate=16000..a=rtpmap:112 G7221/16000. .a=fmtp:112 bitrate=24000..a=rtpmap:6 DVI4/16000..a=rtpmap:0 PCMU/8000..a=rtpmap:8 PCMA/8000..a=rtpmap:4 G723/8000. .a=rtpmap:5 DVI4/8000..a=rtpmap:3 GSM/8000..a=rtpmap:101 telephone- event/8000..a=fmtp: 101 0-16..m=video 14490 RTP/AVP 34 31..a=rtpmap:34 H263/90000..a=rtpmap:31 H261/90000.. U 194.179.25.55:5060 -> 217.125.212.22:10094 SIP/2.0 100 trying -- your call is important to us..Via: SIP/2.0/UDP 172.26.0.52:13552; rport=10094;received=217.125.212.22..From: "chano" <sip:chano@wmserver.hi.inet>; tag=181d13b4-e1f0-4dbd-9606-18e52b57dbf6..To: <sip:raquel@wmserver.hi.inet>..Call-ID: ab9bb0f1-3a43-4ecd-a787-0 3a439714bda@172.26.0.52..CSeq: 1 INVITE..Server: Sip EXpress router (0.8.14 (i386/linux)).. Content-Length: 0..Warning: 392 194.179.25.55:50 60 "Noisy feedback tells: pid=987 req_src_ip=217.125.212.22 req_src_port=10094 in_uri=sip:raquel@wmserver.hi.inet out_uri=sip:80.32.97.245:10052 via_cnt==1".... U 194.179.25.55:5060 -> 80.32.97.245:10052 INVITE sip:80.32.97.245:10052 SIP/2.0..Max-Forwards: 10..Record- Route: <sip:raquel@194.179.25.55;ftag=181d13b4-e1f0-4dbd- 960618e52b57dbf6;lr>..Via: SIP/2.0/UDP 194.179.25.55;branch=z9hG4bK8f9a.26d2ad44.0..Via: SIP/2.0/UDP 172.26.0.52:13552;rport=10094;received=217.125.212.22..From: "chano" <sip:chano@wmserver.hi.inet>;tag=181d13b4-e1f0-4dbd-9606- 18e52b57dbf6..To: <sip:raquel@wmserver.hi.inet>..Call-ID: ab9bb0f1- 3a43-4ecd-a787-03a439714bda@172.26.0.52..CSeq: 1 INVITE..Contact: <sip:217.125.212.22:10094>..User-Agent: Windows RTC/1.0..Content-Type: application/sdp..Content-Length: 529....v=0..o=sayuritra 0 0 IN IP4 172.26.0.52..s=session..c=IN IP4 172.26.0.52..b=CT:1000..t=0 0..m=audio 38370 RTP/AVP 97 111 112 6 0 8 4 5 3 101..a=rtpmap:97 red/8000..a=rtpmap:111 SIREN/16000..a=fmtp:111 bitrate=16000..a=rtpmap:112 G7221/16000..a=fmtp:112 bitrate=24000..a=rtpmap:6 DVI4/16000..a=rtpmap:0 PCMU/8000..a=rtpmap:8 PCMA/8000..a=rtpmap:4 G723/8000..a=rtpmap:5 DVI4/8000..a=rtpmap:3 GSM/8000..a=rtpmap:101 telephone-event/8000..a=fmtp:101 0-16..m=video 14490 RTP/AVP 34 31..a=rtpmap:34 H263/90000..a=rtpmap:31 H261/90000.. U 80.32.97.245:10052 -> 194.179.25.55:5060 SIP/2.0 100 Trying..Via: SIP/2.0/UDP 194.179.25.55;branch=z9hG4bK8f9a.26d2ad44.0..Via: SIP/2.0/UDP 172.26.0.52:13552;rport=10094;received=217.125.212.22..From: "chano" <sip:chano@wmserver.hi.inet>;tag=181d13b4-e1f0-4dbd-9606- 18e52b57dbf6..To: <sip:raquel@wmserver.hi.inet>;tag=4410fcfd-ae51-494e- a0ff-47c34ab309cb..Call-ID: ab9bb0f1-3a43-4ecd-a787- 03a439714bda@172.26.0.52..CSeq: 1 INVITE..User-Agent: Windows RTC/1.0..Content-Length: 0.... U 80.32.97.245:10052 -> 194.179.25.55:5060 SIP/2.0 400 Bad Request..Via: SIP/2.0/UDP 194.179.25.55;branch=z9hG4bK8f9a.26d2ad44.0..Via: SIP/2.0/UDP 172.26.0.52:13552;rport=10094;received=217.125.212.22..From: "chano" <sip:chano@wmserver.hi.inet>;tag=181d13b4-e1f0-4dbd-9606- 18e52b57dbf6..To: <sip:raquel@wmserver.hi.inet>;tag=4410fcfd-ae51-494e- a0ff-47c34ab309cb..Call-ID: ab9bb0f1-3a43-4ecd-a787- 03a439714bda@172.26.0.52..CSeq: 1 INVITE..Record-Route: <sip:raquel@194.179.25.55;ftag=181d13b4-e1f0-4dbd-9606-18e52b57dbf6;lr> ..User-Agent: Windows RTC/1.0..Content-Length: 0.... My ser.cfg is: debug=3 # debug level (cmd line: -dddddddddd) fork=yes log_stderror=yes # (cmd line: -E) check_via=no # (cmd. line: -v) dns=no # (cmd. line: -r) rev_dns=no # (cmd. line: -R) port=5060 children=4 fifo="/tmp/ser_fifo" listen=194.179.25.55 loadmodule "/usr/lib/ser/modules/postgres.so" loadmodule "/usr/lib/ser/modules/sl.so" loadmodule "/usr/lib/ser/modules/tm.so" loadmodule "/usr/lib/ser/modules/rr.so" loadmodule "/usr/lib/ser/modules/maxfwd.so" loadmodule "/usr/lib/ser/modules/usrloc.so" loadmodule "/usr/lib/ser/modules/textops.so" loadmodule "/usr/lib/ser/modules/registrar.so" loadmodule "/usr/lib/ser/modules/uri.so" loadmodule "/usr/lib/ser/modules/domain.so" loadmodule "/usr/lib/ser/modules/mediaproxy.so" loadmodule "/usr/lib/ser/modules/auth.so" loadmodule "/usr/lib/ser/modules/auth_db.so" modparam("usrloc", "db_mode", 2) modparam("usrloc", "user_column", "user_id") modparam("usrloc", "db_url", "sql://ser:ser@localhost:5432/ser") modparam("auth_db", "user_column", "user_id") modparam("auth_db", "db_url", "sql://ser:ser@localhost:5432/ser") modparam("auth_db", "calculate_ha1", yes) modparam("auth_db", "password_column", "password") modparam("domain", "db_mode", 1) modparam("domain", "domain_table", "subscriber") modparam("domain", "db_url", "sql://ser:ser@localhost:5432/ser") modparam("uri", "db_url", "sql://ser:ser@localhost:5432/ser") modparam("uri", "uri_table", "uri") modparam("uri", "uri_user_column", "user_id") modparam("mediaproxy", "natping_interval", 60) modparam("registrar", "nat_flag", 2) route{ if (!mf_process_maxfwd_header("10")) { if (method!="ACK") { sl_send_reply("483", "Too many hops"); }; break; }; if (msg:len >= max_len) { if (method!="ACK") { sl_send_reply("513", "Message too big"); }; break; }; if (method=="REGISTER") { if (is_from_local()) { # Mark as NAT'ed if (client_nat_test("3")) { setflag(2); force_rport(); fix_contact(); }; if (!www_authorize("wmserver.hi.inet", "subscriber")) { www_challenge("wmserver.hi.inet", "0"); break; } else if (!check_to()) { sl_send_reply("403", "Username!=To not allowed"); break; }; if (!save("location")) { sl_reply_error(); }; } else { sl_send_reply("403", "This domain is not served here"); }; break; }; if (method=="INVITE") { if (!(is_from_local() || is_uri_host_local())) { sl_send_reply("403", "Relaying is forbidden"); break; }; t_on_failure("1"); } else if (method == "BYE" || method == "CANCEL") { end_media_session(); }; if (loose_route()) { if (method=="INVITE" || method=="ACK") { use_media_proxy(); }; # end media session for BYE and CANCEL is done above # before entering the loose route. no need to call it here t_relay(); break; }; # Force subsequent messages to pass trough this proxy if (method == "INVITE") { record_route(); }; if (client_nat_test("3") && !search("^Record-Route:")) { # Mark as NAT'ed force_rport(); fix_contact(); }; if (method=="INVITE") { t_on_reply("1"); }; if (is_uri_host_local()) { # join with next if? if (!lookup("location")) { sl_send_reply("404", "User not found"); break; }; }; if (method=="INVITE" || method=="ACK") { use_media_proxy(); }; if (!t_relay()) { if (method=="INVITE" || method=="ACK") { end_media_session(); }; sl_reply_error(); }; } failure_route[1] { end_media_session(); } onreply_route[1] { if (status=~"(183)|(2[0-9][0-9])") { if (client_nat_test("1")) { fix_contact(); }; use_media_proxy(); }; } Any ideas?.Can this problem be solved? Thanks in advance.