ZyWALL 5/35/70 Series User’s Guide

18.2 IPSec Architecture

The overall IPSec architecture is shown as follows.

Figure 144 IPSec Architecture

18.2.1 IPSec Algorithms

The ESP (Encapsulating Security Payload) Protocol (RFC 2406) and AH (Authentication Header) protocol (RFC 2402) describe the packet formats and the default standards for packet structure (including implementation algorithms).

The Encryption Algorithm describes the use of encryption techniques such as DES (Data Encryption Standard), AES (Advanced Encryption Standard) and Triple DES algorithms.

The Authentication Algorithms, HMAC-MD5 (RFC 2403) and HMAC-SHA-1 (RFC 2404, provide an authentication mechanism for the AH and ESP protocols. Refer to Section 19.2 on page 308 for more information.

18.2.2 Key Management

Key management allows you to determine whether to use IKE (ISAKMP) or manual key configuration in order to set up a VPN.

18.3 Encapsulation

The two modes of operation for IPSec VPNs are Transport mode and Tunnel mode.

Chapter 18 Introduction to IPSec

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