ZyXEL Communications ZyWALL 1000 104

Chapter 4 Wizard Setup

Figure 39 VPN Advanced Wizard: Step 3

The following table describes the labels in this screen.

Table 19 VPN Advanced Wizard: Step 3

LABEL	DESCRIPTION
Negotiation Mode	Select Main for identity protection. Select Aggressive 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. AES128 uses a 128-bit key and is faster than 3DES. AES192 uses
	a 192-bit key and AES256 uses a 256-bit key. Select Null to have no
	encryption.

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 SHA1 for 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. DH5 refers to Diffie-Hellman Group 5
	a 1536 bit random number.