What does anti-spoofing work to accomplish?

• A. It encrypts all internal traffic.
• B. It monitors traffic without blocking forged IP addresses.
• C. It detects forged source IP addresses and blocks them.
• D. It only applies to outbound traffic.

Answer: (C)

Anti-spoofing is about stopping IP address spoofing by verifying that a packet’s source address could actually come from the network it’s entering or leaving, and then blocking those that don’t. This is typically done with filtering on network devices, dropping packets with forged source IPs (ingress filtering on incoming traffic and/or egress filtering to prevent spoofed addresses from leaving). The aim is not about encrypting traffic, nor about simply monitoring without taking action, and it isn’t limited to outbound traffic. So the best description is that it detects forged source IP addresses and blocks them.