You are a network designer and you must ensure that the network you design is...

Unicast Reverse Path Forwarding (uRPF)is a security feature that helps mitigate IP spoofing attacks. It checks whether the source of a packet received on an interface matches the best return path to that source in the routing table.

Strict Mode (C):Ensures the source IP address of a packet is reachable via the same interface on which the packet was received. This prevents forged source IP addresses from traversing the network, which is essential in defending against outbound DDoS attacks sourced from infected hosts.

Loose Mode (B):Only verifies that the source IP exists in the routing table (less strict), which might still allow spoofing in multi-homed or asymmetric environments.

uRPF strict mode is the best fit in secure environments with symmetric routing—commonly in enterprise edge or distribution layers.

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