ZyXEL Communications PRESTIGE 652H User Manual page 428

Prestige 652 Series User's Guide
The following table describes the fields in this menu.
FIELD
Phase 1
Negotiation Press [SPACE BAR] to choose from Main or Aggressive and then press
Mode [ENTER]. See earlier for a discussion of these modes. Multiple SAs
connecting through a secure gateway must have the same negotiation mode.
Pre-Shared Prestige gateways authenticate an IKE VPN session by matching pre-shared
Key keys. Pre-shared keys are best for small networks with fewer than ten nodes.
Enter your pre-shared key here. Enter up to 31 characters. Any character may
be used, including spaces, but trailing spaces are truncated.
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 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. Prestige
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 slightly increased latency and decreased throughput.
Press [SPACE BAR] to choose from 3DES or DES and then press [ENTER].
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 slightly slower.
Press [SPACE BAR] to choose from SHA1 or MD5 and then press [ENTER].
SA Life Time Define the length of time before an IKE Security Association automatically
(Seconds) renegotiates in this 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.
42-12
Table 42-3
Menu 27.1.1.1 IKE Setup
DESCRIPTION EXAMPLE
Main
DES
SHA1
28800
(default)
DH1
VPN/IPSec Setup