ZyXEL Communications Prestige 661H Series, User Manual

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Prestige 661H/HW Series User’s Guide
Chapter 15 VPN Screens 180
15.6 Keep Alive
When you initiate an IPSec tunnel with keep alive enabled, the Prestige automatically
renegotiates the tunnel when the IPSec SA lifetime period expires (see
Section 15.11 on page
188 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 Prestige-compatible keep alive
feature enabled in order for this feature to work.
If the Prestige 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
Prestige because the Prestige never drops the tunnels that are already connected.
When there is outbound traffic with no inbound traffic, the Prestige automatically drops the
tunnel after two minutes.
15.7 Remote DNS Server
In cases where you want to use domain names to access Intranet servers on a remote network
that has a DNS server, you must identify that DNS server. You cannot use DNS servers on the
LAN or from the ISP since these DNS servers cannot resolve domain names to private IP
addresses on the remote network
Remote
Address
This is the IP address(es) of computer(s) on the remote network behind the remote
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 Prestige processing requirements and communications
latency (delay).
Secure Gateway
IP
This is the static WAN IP address or URL of the remote IPSec router. This field
displays 0.0.0.0 when you configure the Secure Gateway Address field in the VPN-
IKE screen to 0.0.0.0.
Back Click Back to return to the previous screen.
Table 53 VPN Summary (continued)
LABEL DESCRIPTION