Question: I am studying Security Fundamentals on Networks and as a part of an excercise I have the following question:

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Which of the following statements are true? (Select all that apply)

a.- An IDS deals with malicious traffic that the firewall missed.

b.- An IPS is on the boundary of the trusted inside and the untrusted outside.

c.- A network-based firewall protects hosts from malicious traffic originating on their same network.

d.- An IPS protects hosts from malicious traffic originating on their same network.

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What could be the answers? According to me, **b** and **c** would be the answers because an IPS protects the original traffic that pass through, **b** because it is in the boundary but I have a doubt with option **a** because and IDS as I know makes a copy of the traffic just to analyze it.

Answer: 
The correct answer should be A and D option.

**a.- An IDS deals with malicious traffic that the firewall missed.**

b.- An IPS is on the boundary of the trusted inside and the untrusted outside.

c.- A network-based firewall protects hosts from malicious traffic originating on their same network.

**d.- An IPS protects hosts from malicious traffic originating on their same network.**
Remember the difference between IDS and IPS. Detection and Prevention. Wjile IDS may run on a host and can detect attacks it has no way to prevent them. Since a IPS is on the firewall it can see and stop all malicious traffic.

A, True, since it may be implemented on the hosts (HIDS)

B, True, an IPS must be able to stop malicious traffic

C, False, a firewall is not inspecting packets on the same network

D, False, for the same reason as B