ZyXEL Communications NBG420N - Manual (Page 170)

Chapter 15 IPSec VPN
NBG420N User’s Guide
170
The following table describes the labels in this screen.
Table 63 SECURITY > VPN > Rule Setup: IKE (Basic)
LABEL DESCRIPTION
Property
Active Select this check box to activate this VPN policy.
Keep Alive Select this check box to have the NBG420N automatically reinitiate the SA after
the SA lifetime times out, even if there is no traffic. The remote IPSec router must
also have keep alive enabled in order for this feature to work.
NAT Traversal Select this check box to enable NAT traversal. NAT traversal allows you to set up
a VPN connection when there are NAT routers between the two IPSec routers.
Note: The remote IPSec router must also have NAT traversal
enabled.
You can use NAT traversal with ESP protocol using Transport or Tunnel mode,
but not with AH protocol nor with manual key management. In order for an IPSec
router behind a NAT router to receive an initiating IPSec packet, set the NAT
router to forward UDP ports 500 and 4500 to the IPSec router behind the NAT
router.
IPSec Keying
Mode
Select IKE or Manual from the drop-down list box. IKE provides more protection
so it is generally recommended. Manual is a useful option for troubleshooting if
you have problems using IKE key management.
DNS Server (for
IPSec VPN)
If there is a private DNS server that services the VPN, type its IP address here.
The NBG420N assigns this additional DNS server to the NBG420N's DHCP
clients that have IP addresses in this IPSec rule's range of local addresses.
A DNS server allows clients on the VPN to find other computers and servers on
the VPN by their (private) domain names.
Local Policy Local IP addresses must be static and correspond to the remote IPSec router's
configured remote IP addresses.
Two active SAs can have the same configured local or remote IP address, but not
both. You can configure multiple SAs between the same local and remote IP
addresses, as long as only one is active at any time.
In order to have more than one active rule with the Secure Gateway Address
field set to 0.0.0.0, the ranges of the local IP addresses cannot overlap between
rules.
If you configure an active rule with 0.0.0.0 in the Secure Gateway Address field
and the LAN’s full IP address range as the local IP address, then you cannot
configure any other active rules with the Secure Gateway Address field set to
0.0.0.0.
Local Address For a single IP address, enter a (static) IP address on the LAN behind your
NBG420N.
For a specific range of IP addresses, enter the beginning (static) IP address, in a
range of computers on your LAN behind your NBG420N.
To specify IP addresses on a network by their subnet mask, enter a (static) IP
address on the LAN behind your NBG420N.
Local Address End
/Mask
When the local IP address is a single address, type it a second time here.
When the local IP address is a range, enter the end (static) IP address, in a range
of computers on the LAN behind your NBG420N.
When the local IP address is a subnet address, enter a subnet mask on the LAN
behind your NBG420N.