Vpn Rules (Ike): Network Policy Edit: Port Forwarding - ZyXEL Communications ZYWALL 2 PLUS User Manual

Table 66 SECURITY > VPN > VPN Rules (IKE) > Edit Network Policy (continued)
LABEL
SA Life Time
(Seconds)
Perfect Forward
Secret (PFS)
Enable Replay
Detection
Enable Multiple
Proposals
Apply
Cancel

14.8 VPN Rules (IKE): Network Policy Edit: Port Forwarding

Click SECURITY > VPN and the add network policy (
the VPN-Network Policy -Edit screen. Then, under Virtual Address Mapping Rule, select Many-to-
One as the Type and click the Port Forwarding Rules button to open the following screen. Use this
screen to configure port forwarding for your VPN tunnels to let the ZyWALL forward traffic coming in
through the VPN tunnel to the appropriate IP address on the LAN.
ZyWALL 2 Plus User's Guide
DESCRIPTION
Define the length of time before an IPSec SA automatically renegotiates in this
field. The minimum value is 180 seconds.
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.
Select whether or not you want to enable Perfect Forward Secrecy (PFS) and, if
you do, which Diffie-Hellman key group to use for encryption. Choices are:
NONE - disable PFS
DH1 - enable PFS and use a 768-bit random number
DH2 - enable PFS and use a 1024-bit random number
PFS changes the root key that is used to generate encryption keys for each
IPSec SA. It is more secure but takes more time.
As a VPN setup is processing intensive, the system is vulnerable to Denial of
Service (DOS) attacks. The IPSec receiver can detect and reject old or
duplicate packets to protect against replay attacks. Enable replay detection by
selecting this check box.
Select this to allow the ZyWALL to use any of its phase 2 encryption and
authentication algorithms when negotiating an IPSec SA.
When you enable multiple proposals, the ZyWALL allows the remote IPSec
router to select which phase 2 encryption and authentication algorithms to use
for the IPSec SA, even if they are less secure than the ones you configure for
the VPN rule.
Clear this to have the ZyWALL use only the configured phase 2 encryption and
authentication algorithms when negotiating an IPSec SA.
Click Apply to save the changes.
Click Cancel to discard all changes and return to the main VPN screen.
Chapter 14 IPSec VPN
) icon in the VPN Rules (IKE) screen to display
259