ZyXEL Communications P-2602H manual 253

	Chapter 18 VPN Screens
Table 97 Advanced VPN Policies
LABEL	DESCRIPTION
Pre-Shared Key	Type your pre-shared key in this field. A pre-shared key identifies a
	communicating party during a phase 1 IKE negotiation. It is called "pre-shared"
	because you have to share it with another party before you can communicate
	with them over a secure connection.
	Type from 8 to 31 case-sensitive ASCII characters or from 16 to 62 hexadecimal
	("0-9", "A-F") characters. You must precede a hexadecimal key with a "0x” (zero
	x), which is not counted as part of the 16 to 62-character range for the key. For
	example, in "0x0123456789ABCDEF", “0x” denotes that the key is hexadecimal
	and “0123456789ABCDEF” is the key itself.
	Both ends of the VPN tunnel must use the same pre-shared key. You will receive
	a “PYLD_MALFORMED” (payload malformed) packet if the same pre-shared key
	is not used on both ends.
Encryption	Select DES, 3DES or AES from the drop-down list box.
Algorithm	When you use one of these encryption algorithms for data communications, both
	the sending device and the receiving device must use 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	Select SHA1 or MD5 from the drop-down list box. MD5 (Message Digest 5) and
Algorithm	SHA1 (Secure Hash Algorithm) are hash 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.
SA Life Time	Define the length of time before an IPSec SA automatically renegotiates in this
(Seconds)	field. It may range from 60 to 3,000,000 seconds (almost 35 days).
	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.
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.
Phase 2
Active Protocol	Use the drop-down list box to choose from ESP or AH.
Encryption	This field is available when you select ESP in the Active Protocol field.
Algorithm	Select DES, 3DES, AES or NULL from the drop-down list box.
	When you use one of these encryption algorithms for data communications, both
	the sending device and the receiving device must use 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.
	Select NULL to set up a tunnel without encryption. When you select NULL, you
	do not enter an encryption key.
Authentication	Select SHA1 or MD5 from the drop-down list box. MD5 (Message Digest 5) and
Algorithm	SHA1 (Secure Hash Algorithm) are hash 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.

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P-2602H(W)(L)-DxA User’s Guide