Cisco Certified Internetwork Expert (CCIE) Practice Test

What are three technologies that can be used to trace the source of an attack in a network?

1. Remotely-triggered destination-based black holing

2. ICMP Unreachable messages

3. Sinkholes

4. Traffic scrubbing

The correct answer is: Sinkholes

Using sinkholes is an effective method for tracing the source of an attack in a network. Sinkholes are a type of security mechanism where malicious or unwanted traffic is redirected to a controlled environment. This allows network administrators to analyze the traffic patterns, identify the source IP addresses involved in the attack, and gather intelligence about the attack methods. By examining the captured data, organizations can better understand the attack vectors and take appropriate defensive measures. The other technologies listed, while related to network security and operational responses, serve different purposes that do not primarily focus on tracing the origin of attacks. For instance, remotely-triggered destination-based black holing is generally used to drop unwanted traffic instead of tracing its source. ICMP Unreachable messages help communicate issues with routing or connectivity but do not provide specific source tracing capabilities. Traffic scrubbing focuses on filtering out malicious traffic but is more about mitigation than tracing origins.