ZyXEL Communications ZyXEL ZyWALL 35 - Manual (Page 256)

ZyWALL 35 User’s Guide
254 Chapter 14 VPN Screens
14.11 IKE Phases
There are two phases to every IKE (Internet Key Exchange) negotiation – phase 1
(Authentication) and phase 2 (Key Exchange). A phase 1 exchange establishes an IKE SA and
the second one uses that SA to negotiate SAs for IPSec.
Figure 119 Two Phases to Set Up the IPSec SA
In phase 1 you must:
• Choose a negotiation mode.
• Authenticate the connection by entering a pre-shared key.
• Choose an encryption algorithm.
• Choose an authentication algorithm.
• Choose a Diffie-Hellman public-key cryptography key group (DH1 or DH2).
• Set the IKE SA lifetime. This field allows you to determine how long an IKE SA should
stay up before it times out. An IKE SA times out when the IKE SA lifetime period
expires. If an IKE SA times out when an IPSec SA is already established, the IPSec SA
stays connected.
In phase 2 you must:
AH Select AH if you want to use AH (Authentication Header Protocol). The AH
protocol (RFC 2402) was designed for integrity, authentication, sequence integrity
(replay resistance), and non-repudiation but not for confidentiality, for which the
ESP was designed. If you select AH here, you must select options from the
Authentication Algorithm field (described below).
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.
Advanced Click Advanced to configure more detailed settings of your IKE key management.
Apply Click Apply to save your changes back to the ZyWALL.
Cancel Click Cancel to exit this screen without saving.
Table 77 Edit VPN Rule (continued)
LABEL DESCRIPTION