ZyXEL Communications ZyXEL ZyAIR 100 - Manual (Page 222)

ZyWALL 10~100 Series Internet Security Gateway
15-16 VPN Screens
Figure 15-5 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:
Choose which protocol to use (ESP or AH) for the IKE key exchange.
Choose an encryption algorithm.
Choose an authentication algorithm
Choose whether to enable Perfect Forward Secrecy (PFS) using Diffie-Hellman public-key
cryptography – see section 15.11.3. Select None (the default) to disable PFS.
Choose Tunnel mode or Transport mode.
Set the IPSec SA lifetime. This field allows you to determine how long the IPSec SA should
stay up before it times out. The ZyWALL automatically renegotiates the IPSec SA if there is
traffic when the IPSec SA lifetime period expires. The ZyWALL also automatically
renegotiates the IPSec SA if both IPSec routers have keep alive enabled, even if there is no
traffic. If an IPSec SA times out, then the IPSec router must renegotiate the SA the next time
someone attempts to send traffic.
15.11.1 Negotiation Mode
The phase 1 Negotiation Mode you select determines how the Security Association (SA) will be established
for each connection through IKE negotiations.