CCNAS V1.2 Chapter 08 Implementing Virtual Private Networks.pdf

Organizations use VPNs to create an end-to-end private network connection (tunnel) over third-party networks, such as the Internet or extranets. The tunnel eliminates the distance barrier and enables remote users to access central site network resources. However, VPNs cannot guarantee that the information remains secure while traversing the tunnel. For this reason, modern cryptographic methods are applied to VPNs to establish secure, end-to-end, private network connections.

The IP Security (IPsec) protocol provides a framework for configuring secure VPNs and is commonly deployed over the Internet to connect branch offices, remote employees, and business partners. It is a reliable way to maintain communication privacy while streamlining operations, reducing costs, and allowing flexible network administration.

Secure site-to-site VPNs, between central and remote sites, can be implemented using IPsec. IPsec can also be used in remote-access tunnels for telecommuter access. The Cisco VPN Client is one method for establishing the IPsec remote-access VPN. In addition to IPsec, the Secure Sockets Layer (SSL) protocol can be used to established remote-access VPN connections.