Unicast Reverse Path Forwarding (URPF) is a function 
that checks the validity of the source address of IP 
packets received on an interface. This in an attempt 
to prevent Denial of Service attacks based on IP address 
spoofing.

URPF checks validity of a source address by determining
whether the packet would be successfully routed as a
destination address.

Based on configuration, the check made can be for existence
of any route for the address, or more strictly for a route
out the interface on which the packet was received by the 
device. When a violating packet is detected, it can be dropped.

This MIB allows detection of spoofing events.