Editing VoIP spam (section)

{{External links|date=March 2021}}
{{Use dmy dates|date=April 2020}}
'''VoIP spam''' or '''SPIT''' ([[Spamming|spam]] over [[Internet telephony]]) is unsolicited, automatically dialed telephone calls, typically using [[voice over Internet Protocol]] (VoIP) technology.<ref name=rfc5039>{{cite journal|title= The Session Initiation Protocol (SIP) and Spam (RFC 5039)|year=2008 |url=http://tools.ietf.org/html/rfc5039|publisher=[[Internet Engineering Task Force]]|doi=10.17487/RFC5039 |access-date=14 October 2012|last1=Rosenberg |first1=J. |last2=Jennings |first2=C. |newspaper=Ietf Datatracker |url-access=subscription }}</ref>

VoIP systems, like [[e-mail]] and other Internet applications, are susceptible to abuse by malicious parties who initiate unsolicited and unwanted communications, such as [[Telemarketing|telemarketers]] and [[prank call]]ers. VoIP calling rates are cheap, and the technology provides convenient, often free tools, such as [[Asterisk (PBX)|Asterisk]] and other applications.

The primary underlying technology driving this threat is the [[Session Initiation Protocol]] (SIP),<ref name=rfc3261>{{cite journal|title=SIP: Session Initiation Protocol (RFC 3261)|year=2002 |url=http://tools.ietf.org/html/rfc3261|publisher=[[Internet Engineering Task Force]]|doi=10.17487/RFC3261 |access-date=12 July 2010|last1=Rosenberg |first1=J. |last2=Schulzrinne |first2=H. |last3=Camarillo |first3=G. |last4=Johnston |first4=A. |last5=Peterson |first5=J. |last6=Sparks |first6=R. |last7=Handley |first7=M. |last8=Schooler |first8=E. |newspaper=Ietf Datatracker |url-access=subscription }}</ref> which is a standard for VoIP telecommunications.

Various techniques have been devised to detect spam calls; some take effect even before the recipient has answered a call to disconnect it. These techniques rely on statistical analysis of the features of the call,<ref name=":0" /> such as the originating IP address, or features of the signalling and media messages.<ref name=":1">{{Cite book|last1=Wu|first1=Y. S.|last2=Bagchi|first2=S.|last3=Singh|first3=N.|last4=Wita|first4=R.|title=2009 IEEE/IFIP International Conference on Dependable Systems & Networks |chapter=Spam detection in voice-over-IP calls through semi-supervised clustering |date=June 2009|pages=307–316|doi=10.1109/dsn.2009.5270323|isbn=978-1-4244-4422-9|s2cid=7532017}}</ref>