ZyXEL Communications 2WG 94

Chapter 3 Wizard Setup

Figure 30 VPN Wizard: IKE Tunnel Setting

The following table describes the labels in this screen.

Table 18 VPN Wizard: IKE Tunnel Setting

LABEL	DESCRIPTION
Negotiation Mode	Select Main Mode for identity protection. Select Aggressive Mode to allow
	more incoming connections from dynamic IP addresses to use separate
	passwords.

	Note: Multiple SAs (security associations) connecting through a
	secure gateway must have the same negotiation mode.

Encryption	When DES is used for data communications, both sender and receiver must
Algorithm	know the same secret key, which can be used to encrypt and decrypt the
	message or to generate and verify a message authentication code. The DES
	encryption algorithm uses a 56-bit key. Triple DES (3DES) is a variation on DES
	that uses a 168-bit key. As a result, 3DES is more secure than DES. It also
	requires more processing power, resulting in increased latency and decreased
	throughput. This implementation of AES uses a 128-bit key. AES is faster than
	3DES.
Authentication	MD5 (Message Digest 5) and SHA1 (Secure Hash Algorithm) are hash
Algorithm	algorithms used to authenticate packet data. The SHA1 algorithm is generally
	considered stronger than MD5, but is slower. Select MD5 for minimal security
	and SHA-1for maximum security.

Key Group	You must choose a key group for phase 1 IKE setup. DH1 (default) refers to
	Diffie-Hellman Group 1 a 768 bit random number. DH2 refers to Diffie-Hellman
	Group 2 a 1024 bit (1Kb) random number.

SA Life Time	Define the length of time before an IKE SA automatically renegotiates in this
(Seconds)	field. The minimum value is 180 seconds.
	A short SA Life Time increases security by forcing the two VPN gateways to
	update the encryption and authentication keys. However, every time the VPN
	tunnel renegotiates, all users accessing remote resources are temporarily
	disconnected.