Configure a Black Hole Static Route
About this task
Configure a black hole static route to the destination a router advertises to avoid routing loops after the router aggregates or injects routes to other routers.
If a black hole route is enabled, you must first delete or disable it before you can add a regular static route to that destination.
Note
Only black hole routes that belong to the static type protocol are supported. An inter-VRF black hole route is not installed in the routing table of the destination VRF on the same switch.
Procedure
Example
Create a black hole static route and enable the black hole static route.
Switch:1>enable Switch:1#configure terminal Switch:1(config)#ip route 192.0.2.0 255.255.0.0 255.255.255.255 weight 200 Switch:1(config)#ip route 192.0.2.0 255.255.0.0 255.255.255.255 enable
Variable Definitions
The following table defines parameters for the ip route command.
Variable |
Value |
---|---|
<A.B.C.D A.B.C.D | A.B.C.D/X> |
Specifies the IP address and mask for the route destination in one of the following formats:
255.255.255.255 is the destination of the black hole route. |
enable |
Adds a static route to the router or VRF. |
local-next-hop enable |
Enables the local next hop for this static route. |
next-hop-vrf WORD<1-16> |
Specifies the next-hop VRF instance by name. |
weight <1-65535> |
Specifies the static route cost. Note:
Do not configure a static interface subnet route with a weight of 1. |
preference <1-255> |
Specifies the route preference. |