ZyXEL Communications P-2602 manual Keep Alive, VPN Screens 225, IKE screen to

	P-2602H(W)(L)-DxA Series User’s Guide
Table 81 VPN Setup
LABEL	DESCRIPTION
Remote	This is the IP address(es) of computer(s) on the remote network behind the remote
Address	IPSec router.
	This field displays N/A when the Secure Gateway Address field displays 0.0.0.0. In
	this case only the remote IPSec router can initiate the VPN.
	The same (static) IP address is displayed twice when the Remote Address Type
	field in the VPN-IKE(or VPN-Manual Key) screen is configured to Single.
	The beginning and ending (static) IP addresses, in a range of computers are
	displayed when the Remote Address Type field in the VPN-IKE (or VPN-Manual
	Key) screen is configured to Range.
	A (static) IP address and a subnet mask are displayed when the Remote Address
	Type field in the VPN-IKE(or VPN-Manual Key) screen is configured to Subnet.
Encap.	This field displays Tunnel or Transport mode (Tunnel is the default selection).
IPSec Algorithm	This field displays the security protocols used for an SA.
	Both AH and ESP increase ZyXEL Device processing requirements and
	communications latency (delay).
Secure Gateway	This is the static WAN IP address or URL of the remote IPSec router. This field
IP	displays 0.0.0.0 when you configure the Secure Gateway Address field in the VPN-
	IKE screen to 0.0.0.0.
Modify	Click the Edit icon to go to the screen where you can edit the VPN configuration.
	Click the Remove icon to remove an existing VPN configuration.
Apply	Click this to save your changes and apply them to the ZyXEL Device.
Cancel	Click this return your settings to their last saved values.

17.6 Keep Alive

When you initiate an IPSec tunnel with keep alive enabled, the ZyXEL Device automatically renegotiates the tunnel when the IPSec SA lifetime period expires (see Section 17.12 on page 234 for more on the IPSec SA lifetime). In effect, the IPSec tunnel becomes an “always on” connection after you initiate it. Both IPSec routers must have a ZyXEL Device-compatible keep alive feature enabled in order for this feature to work.

If the ZyXEL Device has its maximum number of simultaneous IPSec tunnels connected to it and they all have keep alive enabled, then no other tunnels can take a turn connecting to the ZyXEL Device because the ZyXEL Device never drops the tunnels that are already connected.

When there is outbound traffic with no inbound traffic, the ZyXEL Device automatically drops the tunnel after two minutes.

Chapter 17 VPN Screens 225