CCNP Routing and Switching ROUTE 300-101 Official Cert Guide

Unicast Reverse Path Forwarding

Lesson 2: Unicast Reverse Path Forwarding

One approach to preventing malicious traffic from entering a network is to use Unicast Reverse Path Forwarding (uRPF). Specifically, uRPF can help block packets having a spoofed IP address. The way that uRPF works is to check the source IP address of a packet arriving on an interface and determine whether that IP address is reachable, based on the router’s Forwarding Information Base (FIB) used by Cisco Express Forwarding (CEF). Optionally, the router can also check to see whether the packet is arriving on the interface the router would use to send traffic back to that IP ...