Lab 10.5.2 Null Interface Alternative

Objectives:

  • Deny traffic to a specific network by using a static route to the null 0 interface.

Equipment Requirements:

  • Two Routers
  • One Switch with two VLANS set or two switches or two hubs
  • Two workstations

Scenario:

We want to stop traffic from the 172.32.4.0 network from reaching the 172.32.2.0 network without the overhead of access-list processing. We will use the null 0 interface to drop all traffic for the 172.32.2.0 network into the proverbial bit bucket.

Step 1

Construct the above circuit, using IGRP as your routing protocol. Use the network address 172.32.3.0/24 on the serial link between the two routers.

Upon completion of the configuration, ping and trace from the 172.32.4.2 workstation to the 172.32.2.2 workstation and vice versa.

NOTE: In windows the command is "tracert 172.32.2.2"

Step 2

On Router A issue the following command:

router-a(config)#ip route 172.32.2.0 255.255.255.0 null 0
router-a(config)#^Z

Step 3

On Router A issue the commands show ip route and ping 172.32.2.1 . Record your findings below:

Step 4

On the workstation with IP address 172.32.4.2, attempt to ping 172.32.2.2

Was the ping successful?

Step 5

On the workstation with IP address 172.32.2.2, attempt to ping to 172.32.4.2

Was the ping successful?