Manual Key Setup; Configuring Edit Manual Setup - ZyXEL Communications ZyXEL ZyWALL 2WE User Manual

ZyWALL 2 and ZyWALL 2WE
LABEL
Authentication
Algorithm
SA Life Time
Perfect Forward
Secrecy (PFS)
Basic
Click Apply to save your changes. Click Reset to begin configuring this screen afresh.

27.12 Manual Key Setup

Manual key management is useful if you have problems with IKE key management.
27.12.1 Security Parameter Index (SPI)
An SPI is used to distinguish different SAs terminating at the same destination and using the same IPSec
protocol. This data allows for the multiplexing of SAs to a single gateway. The SPI (Security Parameter
Index) along with a destination IP address uniquely identify a particular Security Association (SA). The SPI
is transmitted from the remote VPN gateway to the local VPN gateway. The local VPN gateway then uses
the network, encryption and key values that the administrator associated with the SPI to establish the tunnel.
Current ZyXEL implementation assumes identical outgoing and incoming SPIs.

27.13 Configuring Edit Manual Setup

To edit manual setup, select one of the VPN rules in the VPN Summary screen and click Edit to configure
the rule's settings. The basic IKE rule setup screen opens
27-20
Table 27-8 Advanced
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.
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.
Perfect Forward Secrecy (PFS) is disabled (None) by default in phase 2 IPSec SA
setup. This allows faster IPSec setup, but is not so secure. Choose from DH1 or DH2 to
enable PFS. DH1 refers to Diffie-Hellman Group 1, a 768 bit random number. DH2
refers to Diffie-Hellman Group 2, a 1024 bit (1Kb) random number (more secure, yet
slower).
Click Basic to go to the previous VPN configuration screen.
IKE VPN Rule Setup
DESCRIPTION
VPN/IPSec Setup