If not, routing loops may occur when outside hosts attempt to reach IP addresses not currently assigned to a dialed in client but are part of the summary route. In this type of configuration, the access server should have that same summary route pointing to the access server Null0 interface. To ensure reachability to these clients, while not flooding the entire network with host routes, other routers in the network typically have a summary route which points to the access server. This scenario causes host routes to be installed in the access server routing table. ExampleĪ common scenario where you may need to add a static route to Null0 is that of an access server which has many clients dialing in.
#255 255 255 0.8 how to
The next section presents an example of how to use the ip route command to create a static route to Null0. Refer to the ip route section of Chapter: IP Routing Protocol-Independent Commands A through Rįor more information about the ip route command. Command SyntaxĪ static route to Null0 is a normal static route, except that it points to the Null0 interface, which is a virtual IOS interface. Conventionsįor more information on document conventions, refer to Cisco Technical Tips Conventions. If you are working in a live network, ensure that you understand the potential impact of any command before using it. All of the devices used in this document started with a cleared (default) configuration. The information presented in this document was created from devices in a specific lab environment.
#255 255 255 0.8 software
The information in this document is based on the software and hardware versions below:
There are no specific prerequisites for this document. Because not all IP addresses are always in use, there is a risk of looping packets in case default routes are used on the router which receives the traffic for the summary. Whenever a routing protocol summarizes, this means that the router might receive traffic for any IP address within that summary.
Enhanced Interior Gateway Routing Protocol (EIGRP), for instance, always creates a route to the Null0 interface when it summarizes a group of routes. The Null interface is typically used for preventing routing loops.
0 kommentar(er)
