Wikipedia
A virtual private network (VPN) extends a private network across a public network and enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network Applications running across a VPN may therefore benefit from the functionality, security, and management of the private network Encryption is a common, although not an inherent, part of a VPN connectionVPN technology was developed to provide access to corporate applications and resources to remote or mobile users, and to branch offices For security, the private network connection may be established using an encrypted layered tunneling protocol, and users may be required to pass various authentication methods to gain access to the VPN
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