What is null route?

A null route or black hole route is a network route (routing table entry) that goes nowhere. Matching packets are dropped (ignored) rather than forwarded, acting as a kind of very limited firewall. The act of using null routes is often called blackhole filtering.

What is null route Cisco?

Null 0 routing is used to prevent routing loops in some conditions as if any packet is destinated for some specific route in that subnet which is not available for an example is down due to any reason instead of going through the default route and packet reaching somewhere else packet destined for that specific route …

What is a null static route?

A static route to Null0 is a normal static route, except that it points to the Null0 interface, which is a virtual IOS interface. Refer to the ip route section of Chapter: IP Routing Protocol-Independent Commands A through R for more information about the ip route command.

What does null route mean in computer networking?

In computer networking, a null route (blackhole route) is a network route (routing table entry) that goes nowhere. Matching packets are dropped (ignored) rather than forwarded, acting as a kind of very limited firewall.

How to create a static route to null0?

The next section presents an example of how to use the ip route command to create a static route to Null0. A 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. This scenario causes host routes to be installed in the access server routing table.

What do you call the Act of null routing?

The act of using null routes is often called blackhole filtering. The rest of this article deals with null routing in the Internet Protocol (IP).

How to drop IP address with Null routes?

While traversing the RPDB, any route lookup which matches a rule with the blackhole rule type will cause the packet to be dropped. No ICMP will be sent and no packet will be forwarded. The syntax is follows for the ip command: # ip route add blackhole 202.54.5.2/29