Network Security - Explain what is meant by an IDS and an IPS

Network Security

A. In no less than 250 words, explain what is meant by an IDS and an IPS.  How are they different?  How are they connected to a network?  

List a few examples of IDS/IPS tools that are currently on the market.

B. Please answer below in a sentence each

1 List and briefly define three classes of intruders.

2 What are two common techniques used to protect a password file?

3 What are three benefits that can be provided by an intrusion detection system?

4 What is the difference between statistical anomaly detection and rule-based intrusion detection?

5 What metrics are useful for profile-based intrusion detection?

6 What is the difference between rule-based anomaly detection and rule-based penetration identification?

7 What is a honeypot?

8 What is a salt in the context of UNIX password management?

9 List and briefly define four techniques used to avoid guessable passwords.