Choosing The Wan Failure Method - NETGEAR DGFV338 ProSafe Reference Manual

DGFV338 ProSafe Wireless ADSL Modem VPN Firewall Router Reference Manual
• Auto-Rollover using WAN port. If you have configured both the ADSL ISP and Ethernet ISP
WAN ports of the DGFV338, you can select Auto-Rollover for increased system reliability. In
Auto-Rollover mode, you select one WAN interface to be the primary Internet connection and
the other is a backup connection in case the primary connection fails. As long as the primary
connection is up, all traffic is sent over the primary WAN interface. Once the primary
connection goes down, the backup WAN interface is brought up to send the traffic. When the
primary port is restored, the DGFV338 will automatically switch back to the primary port.
• Use Dedicated WAN port.
– Dedicated ADSL. If you have configured only the ADSL ISP, then select ADSL as the
Dedicated WAN port. The ADSL WAN interface will always be active and all traffic will
be sent over this link; the other link will always be down. No link failure detection will
occur.
– Dedicated Ethernet. If you have configured only the Ethernet ISP, then select Ethernet as
the Dedicated WAN port. In this mode the 10/100 Ethernet WAN interface will always be
active and all traffic will be sent over this link; the other link will always be down. No link
failure detection will occur.

Choosing the WAN Failure Method

When Auto-Rollover is configured, the DGFV338 detects WAN failure by sending DNS queries to
a DNS server, or by sending ICMP ping requests to an IP address. Each configured WAN interface
sends DNS queries or ping requests. If replies are not received, the corresponding WAN interface
is considered down.
If Auto-Rollover is configured, select one of these methods for WAN failure detection:
• DNS lookup using WAN DNS Servers (ISP DNS Servers). DNS queries are sent to the DNS
server configured on the ADSL and Ethernet ISP pages.
• DNS lookup using this DNS Server (for example, a public DNS Server). DNS queries are
sent to a public DNS server address that you specify.
• Ping to this IP address. Enter a public IP address that will not reject the Ping request or will
not consider the traffic abuse.
You can configure these additional WAN failure detection settings:
• Test Period. A query is sent periodically after every test period. The default test period is 30
seconds.
Basic Installation and Configuration
v1.0, May 2008
2-17