ZyXEL Communications 2602H Series 17.3 My IP Address, 17.2.2 ESP (Encapsulating Security Payload) Protocol

Prestige 2602H/HW Series User’s Guide

17.2.2 ESP (Encapsulating Security Payload) Protocol

The ESP protocol (RFC 2406) provides encryption as well as the services offered by AH. ESP authenticating properties are limited compared to the AH due to the non-inclusion of the IP header information during the authentication process. However, ESP is sufficient if only the upper layer protocols need to be authenticated.

An added feature of the ESP is payload padding, which further protects communications by concealing the size of the packet being transmitted.

Table 66 AH and ESP

	ESP	AH
	DES (default)	MD5 (default)
	Data Encryption Standard (DES) is a widely	MD5 (Message Digest 5) produces a 128-bit
	used method of data encryption using a	digest to authenticate packet data.
	private (secret) key. DES applies a 56-bit key
	to each 64-bit block of data.
	3DES	SHA1
	Triple DES (3DES) is a variant of DES, which	SHA1 (Secure Hash Algorithm) produces a
	iterates three times with three separate keys	160-bit digest to authenticate packet data.
ENCRYPTION	(3 x 56 = 168 bits), effectively doubling the
	strength of DES.
	AES
	Advanced Encryption Standard is a newer
	method of data encryption that also uses a
	secret key. This implementation of AES
	applies a 128-bit key to 128-bit blocks of data.
	AES is faster than 3DES.
	Select NULL to set up a phase 2 tunnel
	without encryption.
	MD5 (default)	MD5 (default)
	MD5 (Message Digest 5) produces a 128-bit	MD5 (Message Digest 5) produces a 128-bit
	digest to authenticate packet data.	digest to authenticate packet data.
AUTHENTICATION	SHA1	SHA1
	SHA1 (Secure Hash Algorithm) produces a	SHA1 (Secure Hash Algorithm) produces a
	160-bit digest to authenticate packet data.	160-bit digest to authenticate packet data.
	Select MD5 for minimal security and SHA1 for maximum security.

17.3 My IP Address

My IP Address is the WAN IP address of the Prestige. The Prestige has to rebuild the VPN tunnel if the My IP Address changes after setup.

The following applies if this field is configured as 0.0.0.0:

•The Prestige uses the current Prestige WAN IP address (static or dynamic) to set up the VPN tunnel.

214 Chapter 17 VPN Screens