ZyXEL Communications 10 - Manual (Page 361)

ZyWALL 10~100 Series Internet Security Gateway
VPN/IPSec Setup 29-3
Table 29-1 AH and ESP
ESP AH
Select DES for minimal security and 3DES for maximum.
Select NULL to set up a tunnel without encryption. Select MD5 for minimal security and SHA-1 for
maximum security.
DES (default)
Data Encryption Standard (DES) is a widely used method
of data encryption using a private (secret) key. DES
applies a 56-bit key to each 64-bit block of data. MD5 (default)
MD5 (Message Digest 5) produces a 128-bit
digest to authenticate packet data.
3DES
Triple DES (3DES) is a variant of DES, which iterates
three times with three separate keys (3 x 56 = 168 bits),
effectively doubling the strength of DES. SHA1
SHA1 (Secure Hash Algorithm) produces a
160-bit digest to authenticate packet data.
29.3 IPSec Summary
Type 1 in menu 27 and then press [ENTER] to display Menu 27.1 — IPSec Summary. This is a summary
read-only menu of your IPSec rules (tunnels). Edit or create an IPSec rule by selecting an index number and
then configuring the associated submenus.
The following figure helps explain the main fields in menu 27.1.
Figure 29-3 IPSec Summary Fields
Local and remote IP addresses must be static.
29.3.1 Keep Alive
A tunnel with no outbound or inbound traffic is "idle" and stays connected until the IPSec SA lifetime period
expires (see section 29.5). The ZyWALL automatically renegotiates the IPSec SA if there is traffic when the