ZyXEL Communications 650 Series Manual De Usuario

Descargar
Página de 513
Prestige 650 Series User’s Guide 
16-18  
VPN 
Screens 
Table 16-8 VPN IKE: Advanced 
LABEL  
DESCRIPTION 
Encryption 
Algorithm 
Select DES or 3DES from the drop-down list box.  
When DES is used for data communications, both sender and receiver must 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.  
Authentication 
Algorithm 
Select SHA1 or MD5 from the drop-down list box. MD5 (Message Digest 5) and 
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-1 for maximum security.  
SA Life Time 
(Seconds)
 
Define the length of time before an IKE SA automatically 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.  
Phase 2 
 
Active Protocol   Use the drop-down list box to choose from ESP or AH.  
Encryption 
Algorithm 
Select DES3DES or NULL from the drop-down list box.  
When DES is used for data communications, both sender and receiver must 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. Select NULL to set up a 
tunnel without encryption. When you select NULL, you do not enter an encryption 
key.