Black Hole Filtering is effective in preventing IP spoofing at which network level?

Black Hole Filtering is effective in preventing IP spoofing at which network level?

• A. ISP level
• B. Local network
• C. End-user device
• D. Core backbone network

Answer: (A)

Black Hole Filtering works by discarding traffic that is identified as spoofed, effectively dropping it to prevent attackers from using misrepresented IP addresses to reach targets. This approach is most effective at the ISP level because the provider controls the network edge where traffic enters and leaves the Internet. By implementing null routes or black holes at the border, spoofed packets can be stopped before they flood downstream networks or reach victims. Local networks and end-user devices can apply filtering, but spoofed traffic from outside their own domain will still traverse them unless upstream filtering is in place. The core backbone network isn’t ideal for broad black-holing because it risks dropping legitimate traffic across many customers and is harder to manage with precision.

Black Hole Filtering works by discarding traffic that is identified as spoofed, effectively dropping it to prevent attackers from using misrepresented IP addresses to reach targets. This approach is most effective at the ISP level because the provider controls the network edge where traffic enters and leaves the Internet. By implementing null routes or black holes at the border, spoofed packets can be stopped before they flood downstream networks or reach victims. Local networks and end-user devices can apply filtering, but spoofed traffic from outside their own domain will still traverse them unless upstream filtering is in place. The core backbone network isn’t ideal for broad black-holing because it risks dropping legitimate traffic across many customers and is harder to manage with precision.