The PE router must be configured with Unicast Reverse Path Forwarding (uRPF) loose mode enabled on all CE-facing interfaces..
Overview
Finding ID
Version
Rule ID
IA Controls
Severity
V-207140
SRG-NET-000205-RTR-000008
SV-207140r604135_rule
Medium
Description
The uRPF feature is a defense against spoofing and denial-of-service (DoS) attacks by verifying if the source address of any ingress packet is reachable. To mitigate attacks that rely on forged source addresses, all provider edge routers must enable uRPF loose mode to guarantee that all packets received from a CE router contain source addresses that are in the route table.