VPN" redirects here. For other uses, see VPN (disambiguation).
VPN Connectivity overviewA virtual private network (VPN) is a network that uses primarily publictelecommunication infrastructure, such as the Internet, to provide remote offices or traveling users access to a central organizational network.
VPNs typically require remote users of the network to beauthenticated, and often secure data with encryption technologies to prevent disclosure of private information to unauthorized parties.
VPNs may serve any network functionality that is found on anynetwork, such as sharing of data and access to network resources, printers, databases, websites, etc. A VPN user typically experiences the central network in a manner that is identical to being connecteddirectly to the central network. VPN technology via the public Internet has replaced the need to requisition and maintain expensive dedicated leased-line telecommunication circuits once typical inwide-area network installations.
Secure VPNs use cryptographic tunneling protocols to provide confidentiality by blocking intercepts and packet sniffing, allowing senderauthentication to block identity spoofing, and provide message integrity by preventing message alteration.
Secure VPN protocols include the following:
IPsec (Internet Protocol Security) was developed bythe Internet Engineering Task Force (IETF), and was initially developed for IPv6, which requires it. This standards-based security protocol is also widely used with IPv4. Layer 2 Tunneling Protocolfrequently runs over IPsec. Its design meet the most security goals: authentication, integrity, and confidentiality. IPsec functions by summarizing an IP packet in conjunction with a surrounding packet,and encrypting the outcome.
Transport Layer Security (SSL/TLS) can tunnel an entire network's traffic, as it does in the OpenVPN project, or secure an individual connection. A number of vendors...