Using Static Routes - NETGEAR FVM318 Reference Manual

Reference Manual for the Model FVM318 Cable/DSL ProSafe Wireless VPN Security Firewall
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.

Using Static Routes

Static Routes provide additional routing information to your firewall. Under normal
circumstances, the firewall has adequate routing information after it has been configured for
Internet access, and you do not need to configure additional static routes. You must configure
static routes only for unusual cases such as multiple routers or multiple IP subnets located on your
network.
As an example of when a static route is needed, consider the following case:
• Your primary Internet access is through a cable modem to an ISP.
• You have an ISDN router on your home network for connecting to the company where you are
employed. This router's address on your LAN is 192.168.0.100.
• Your company's network is 134.177.0.0.
When you first configured your firewall, two implicit static routes were created. A default route
was created with your ISP as the gateway, and a second static route was created to your local
network for all 192.168.0.x addresses. With this configuration, if you attempt to access a device on
the 134.177.0.0 network, your firewall will forward your request to the ISP. The ISP forwards your
request to the company where you are employed, and the request will likely be denied by the
company's firewall.
In this case you must define a static route, telling your firewall that 134.177.0.0 should be accessed
through the ISDN router at 192.168.0.100. The static route would look like
In this example:
• The Destination IP Address and IP Subnet Mask fields specify that this static route applies to
all 134.177.x.x addresses.
• The Gateway IP Address fields specifies that all traffic for these addresses should be
forwarded to the ISDN router at 192.168.0.100.
7-8
Figure 7-3.
Advanced Configuration