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vpn

2 kinds of connections over public network

  1. List line

  • ISP gives a dedicated link

  • Very expensive link

  1. VPN

  • Creates tunnels that allow users to connect over a public network

VPN Architecture

Remote Access VPN/ Client-to-site VPN

  • External users connecting to an internal network through one VPN gateway/server.

  • Only one VPN device

  • Normally, a piece of software is installed in the user's device

Site-to-Site VPN

  • Two VPN appliances

  • Connects two separate networks

  • No requirement to download any software to access resources in the other network.

VPN Encryption Protocols

TLS/SSL VPN

  • Used in client-to-site VPN

IPSec VPN

  • Contains several protocols

Key IPSec Protocols

Authentication Header (AH) Protocol

  • provides authentication, does not support encryption

  • mildly obsolete

Encapsulation Security Payload (ESP) Protocol

  • provides encryption and authentication

Internet Key Exchange (IKE) Protocol

  • Negotiation of VPN connection tunnel (called security association)

  • Has two phases - Phase 1 and Phase 2

    • Phase 1 - establish a secure channel for communication

    • Phase 2 - Data packets will go through

Configuration Steps

Checklist

  1. Configure L3 Interface

  2. Configure Tunnel Interface

  3. Configure a new Static Route

  4. Setup Crypto Profile

  5. Setup IKE Gateway

  6. Setup IPSec Tunnel

  7. Security Policy

  8. Test Connection

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