Dear List if ACK message after INVITE message (UAC caller ) can not send to UAC callee. can i do something on openser to complete this 3 way handshaking. openser server bedind NAT best Somsak Vattanavakin 2753-7 Ladprao 99-101 Bangkok.10310 Thailand Tel. (66)0-29350016 , 0-25386251 Fax. (66)0-25140253 www.infowavenet.com