DGFV338 ProSafe Wireless ADSL Modem VPN Firewall Router Reference Manual
The default time to roll over after the primary WAN interface fails is 2 minutes (e.g., a 30- second minimum test period, times a minimum of four tests).
Configuring Dynamic DNS (If Needed)
Note: If your ISP assigns a private WAN IP address such as 192.168.x.x or 10.x.x.x, the 
dynamic DNS service will not work because private addresses will not be routed
on the Internet.
If your network has a permanently assigned (static or fixed) IP address, you can register a domain name and have that name linked with your IP address by public Domain Name Servers (DNS). However, if your Internet account uses a dynamically assigned IP address, you will not know in advance what your IP address will be, and the address can change frequently. In this case, you can use a commercial dynamic DNS service, which allows you to register an extension to its domain, and resolves DNS requests for the resulting FQDN to your
For rollover mode, you will need a fully qualified domain name (FQDN) to implement features such as exposed hosts and virtual private networks regardless of whether you have a fixed or dynamic IP address.
The gateway contains a client that can connect to a dynamic DNS service provider. To use this feature, you must select a service provider and obtain an account with them. After you have configured your account information in the gateway, whenever your
Basic Installation and Configuration |