| 6.1 |  | Virtual Private Networks |
| 6.1.2 |  | Site-to-site VPN |

| 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, firewalls, or VPN concentrators.