A Virtual Private Network (VPN) provides the same network connectivity for
remote users over a public infrastructure as they would have over a private
network. VPN services for network connectivity include authentication, data
integrity, and confidentiality. There are two basic VPN types:
- LAN-to-LAN VPNs – There are two common types of LAN-to-LAN VPNs, also known
as site-to-site VPNs:
- Intranet VPNs connect corporate headquarters, remote offices, and branch
offices over a public infrastructure.
- Extranet VPNs link customers, suppliers, partners, or communities of
interest to a corporate Intranet over a public infrastructure.
- Remote Access VPNs – Which securely connect remote users, such as mobile
users and telecommuters, to the enterprise.
Site-to-site VPNs
Site-to-site VPNs can be used to connect
corporate sites. In the past, a leased line or Frame Relay connection was
required to connect sites. Currently, most corporations have Internet access.
With Internet access, expensive leased lines and Frame Relay lines can be
replaced with site-to-site VPNs. Site-to-site VPNs can be used to provide the
network connection. VPNs can support company intranets and business partner
extranets. Site-to-site VPN is an extension of a classic WAN network.
Site-to-site VPNs can be built using routers, Security Appliances, or VPN
concentrators
.