22-44
Figure 22-4 URPF application situation
In the above figure, Router A sends requests to the server Router B by faking messages whose source
address are 2.2.2.1/8 .In response, Router B will send the messages to the real ā2.2.2.1/8ā. Such illegal
messages attack both Router B and Router C. The application of URPF technology in the situation described
above can avoid the attacks based on the Source Address Spoofing.
22.4.2 URPF Configuration Task Sequence
1. Enable URPF
2. Display and debug URPF relevant information
1. Globally enable URPF
urpf enable
Globally enable and disable URPF.
2. Display and debug URPF relevant information
show urpf
Display which interfaces have been
enabled with URPF function.
22.4.3 URPF Typical Example
SW3
Globally enable
E1/0/8
E1/0/8
10.1.1.10/24
vlan1
E1/0/2
Vlan3
Vlan4