ZyXEL Communications P-793H User Manual

Chapter 11 IPSec VPN

P-793H User’s Guide

The following table describes the fields in this screen.

Table 52   VPN > Setup > Edit

IPSec Setup

Active

Select this check box to activate this VPN policy. This option determines whether 

a VPN rule is applied before a packet leaves the firewall.

Keep Alive

Select either Yes or No from the drop-down list box. 
Select Yes to have the ZyXEL Device 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 if you want to set up a VPN tunnel when there are NAT 

routers between the ZyXEL Device and remote IPSec router. The remote IPSec 

router must also enable NAT traversal, and the NAT routers have to forward UDP 

port 500 packets to the remote IPSec router behind the NAT router.

Name

Type up to 32 characters to identify this VPN policy. You may use any character, 

including spaces, but the ZyXEL Device drops trailing spaces.

IPSec Key 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. 

Negotiation Mode

Select Main or Aggressive from the drop-down list box. Multiple SAs connecting 

through a secure gateway must have the same negotiation mode. 

Encapsulation 

Mode

Select Tunnel mode or Transport mode from the drop-down list box. 

DNS Server (for 

IPSec VPN)

If there is a private DNS server that services the VPN, type its IP address here. 

The ZyXEL Device assigns this additional DNS server to the ZyXEL Device'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

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 

Type

Use the drop-down menu to choose Single, Range, or Subnet. Select Single for 

a single IP address. Select Range for a specific range of IP addresses. Select 

Subnet to specify IP addresses on a network by their subnet mask.

IP Address Start 

When the Local Address Type field is configured to Single, enter a (static) IP 

address on the LAN behind your ZyXEL Device. When the Local Address Type 

field is configured to Range, enter the beginning (static) IP address, in a range of 

computers on your LAN behind your ZyXEL Device. When the Local Address 

Type field is configured to Subnet, this is a (static) IP address on the LAN behind 

your ZyXEL Device.