Hairpin

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What Does Hairpin Mean?

Hairpin refers to telephone systems and the process of sending a call back in the direction of its point of origin. If a call cannot be directed over Internet Protocol to a gateway closer to the target telephone, the call is often redirected back to the local zone, which is the direction of its origination.

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Techopedia Explains Hairpin

The term hairpin comes from the shape of a woman’s hairpin, which doubles back over itself, creating two "legs." In telephony, a single call may be turned into a two-legged call. The two legs intersect at the destination number. The first leg is the call from the source number to the destination number, while the second is the call redirected back from the called number. The term hairpin was also later used in digital data networks to denote an existing feature in some network address translations (NATs) where more than one host is placed behind an NAT. Each host is assigned a certain external address and port by the NAT.

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Margaret Rouse
Technology Expert
Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.