An overview of static routes and their use cause.

A static route is a manually configured route, which, in general, cannot be updated dynamically from information about the network topology learned by the vRouter. However, if a link fails, the router removes the routes, including static routes, from the Routing Information Base (RIB) that use this interface to reach the next hop.

Usually, static routes should be used only for very simple network topologies, or to override the behavior of a dynamic routing protocol for a small number of routes.

The collection of all routes the router learns from its configuration, or from its dynamic routing protocols, is stored in its RIB.

Unicast routes are directly used to determine the forwarding table for unicast packet forwarding.

Blackhole routes are static unreachable routes that can be configured to send ICMP unreachable responses on packets.

Examples of static routes and their related commands.

Static routes presents sample configurations of basic static routes. When you are finished with Configuring static routes, the system is configured as shown in the figure. In the example, a static route is created that says, in effect, “any packets destined for the 11.0.0.0/8 network should be forwarded to 172.16.0.26.”

This section includes the following example:

• Configuring static routes

Configuring static routes shows how to create a static route to the 11.0.0.0/8 network that is directed toward 172.16.0.26.

To create a static route, perform the following steps in configuration mode.

vyatta@R1# set protocols static route 11.0.0.0/8 next-hop 172.16.0.26

vyatta@R1# commit

vyatta@R1# show protocols static route
 route 11.0.0.0/8 {
	next-hop 172.16.0.26 {
	}
}

A description of floating static routes and how to configure them.

Usually, static routes have a relatively short administrative distance—typically 1, and normally shorter than the administrative distances for dynamic (learned) routes. A “floating” static route is a static route with an administrative distance greater than the administrative distance for dynamic routes.

You can configure a static route to be a floating route by setting the administrative distance higher than the distance applied to the routes in your dynamic routing protocol. This higher distance renders the static route less desirable than a dynamic route. At the same time, if the dynamic route is lost, the static route is available to take over traffic, which can be forwarded through the static route as an alternate path.

How to show static routes in the routing table and the related commands.

To display route information, use the show ip route command. To show just static routes, use the show ip route static command, as shown in the following example.

vyatta@R1:~$ show ip route static
Codes: K - kernel route, C - connected, S - static, R - RIP, O - OSPF,
       I - ISIS, B - BGP, > - selected route, * - FIB route
S>* 11.0.0.0/8 [1/0] via 172.16.0.26, dp0p0p0
vyatta@R1:~$

How to configure static IPv6 routes and their related commands.

Static IPv6 routing example shows an IPv6 network with three nodes. Verify that IPv6 forwarding is enabled shows how to configure nodes that use static routes to enable R2 and R4 to communicate through R1.