CCIE Practical Studies: Security (CCIE Self-Study)

Virtual Private Network (VPN) Overview

A VPN can be defined as a method to securely transmit private data over a public infrastructure. In practice, a VPN is effectively an encrypted tunnel over a public network such as the Internet. A tunnel is created between the two VPN endpoints. Data is encrypted before leaving the local VPN endpoint and is decrypted upon arriving at the remote VPN endpoint, ensuring data privacy and security.

Traditional connectivity relies on expensive physical private circuits to connect sites. VPNs rely on the largest, most resilient network in the world—the Internet.

There are two distinct types of VPNs: site-to-site (often separated into intranet and extranet) and remote-access. The following sections describe both ...