hi all, I am very new in sofia sip, and I am develop one register module for FS using sofia sip stack. in FS, when i receive REGISTER message, i am trying to send it to another registrar server (kamailio). I have implement my code in incoming REGISTER message like: nua_set_params(profile->nua, SIPTAG_FROM_STR("sip:101@192.168.1.112:5062"), NUTAG_ENABLEMESSAGE(1), NUTAG_ENABLEINVITE(1), NUTAG_AUTOALERT(1), NUTAG_SESSION_TIMER(0), NUTAG_AUTOANSWER(0), TAG_NULL()); nua_register(nh, NUTAG_PROXY("sip:192.168.1.112:5062"), NUTAG_REGISTRAR("sip:192.168.1.112:5062"), //registra uri SIPTAG_FROM_STR("sip:192.168.1.112:5062"), NUTAG_INSTANCE (0), NUTAG_M_USERNAME("101"), TAG_NULL()); I have one account 101/xxxx in kamailio, i want to register from softphone to FS, FS send register and process authentication with kamailio, then return 200OK back to softphone. With this code bellow, i send REGISTER message and get response in kamailio as: send 613 bytes to udp/[192.168.1.112]:5062 at 03:10:42.833439: ------------------------------------------------------------------------ REGISTER sip:101@192.168.3.122:42806;rinstance=7742cc70900998e8 SIP/2.0 Via: SIP/2.0/UDP 192.168.1.112;rport;branch=z9hG4bKBB44UFQ9ySjQK Max-Forwards: 70 From: <sip:192.168.1.112:5062>;tag=DXeN4j2DFt27j To: "101" <sip:101@192.168.1.112>;tag=cd424d7d Call-ID: ac980e34-4e79-1231-71ba-3e508d3991e2 CSeq: 45210457 REGISTER Contact: <sip:101@192.168.1.112> User-Agent: FreeSWITCH-mod_sofia/1.5.2b+git~20130527T075833Z~f3541e00f4 Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, INFO, UPDATE, REGISTER, REFER, NOTIFY, PUBLISH, SUBSCRIBE Supported: timer, precondition, path, replaces Content-Length: 0 recv 325 bytes from udp/[192.168.1.112]:5062 at 03:10:42.834220: ------------------------------------------------------------------------ SIP/2.0 404 Not here Via: SIP/2.0/UDP 192.168.1.112;rport=5060;branch=z9hG4bKBB44UFQ9ySjQK From: <sip:192.168.1.112:5062>;tag=DXeN4j2DFt27j To: "101" <sip:101@192.168.1.112>;tag=cd424d7d Call-ID: ac980e34-4e79-1231-71ba-3e508d3991e2 CSeq: 45210457 REGISTER Server: kamailio (4.0.1 (x86_64/linux)) Content-Length: 0 Then, I see that structure of SIP REGISTER message is not correct. Can some one help me to construct this message to send to kamailio ? May we dont care about nua_create ? just using nua_set_params or nua_register or nua_options ? Thank all in advance. ThanhTruong