Several times now, in the middle of the night, one of the phones connected to my 'test' installation of 3CX V10 would ring. I would answer it and no one would be there. The Caller ID would show "asterisk". Last night, when this happened again, I looked at the Server Activity Log. Here's what it shows: ======================================================================================== 02:21:52.191 [CM500002]: Unidentified incoming call. Review INVITE and adjust source identification: INVITE sip:email@example.com SIP/2.0 Via: SIP/2.0/UDP 184.108.40.206:54979;branch=z123RE8gBkor3;rport=54979 Max-Forwards: 70 Contact: <sip:firstname.lastname@example.org> To: <sip:email@example.com> From: "asterisk"<sip:firstname.lastname@example.org>;tag=z321RE8gBkor3 Call-ID: email@example.com CSeq: 102 INVITE Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO Supported: replaces User-Agent: Asterisk PBX Content-Length: 0 02:21:52.191 [CM302001]: Authorization system can not identify source of: SipReq: INVITE firstname.lastname@example.org tid=3705f49279c462b5afce137ca121b51b cseq=INVITE email@example.com / 102 from(wire) ======================================================================================== The IP address from which this "unidentified incoming call" came from is in the Czech Republic. Is this an attempt by someone to hack into what they think is an Asterisk-based system? John Rayfield, Jr.