List and describe at least four reasons to acquire and use an IDPS.

What will be an ideal response?

1. To prevent problem behaviors by increasing the perceived risk of discovery and punishment for those who would attack or otherwise abuse the system2. To detect attacks and other security violations that are not prevented by other security measures3. To detect and deal with the preambles to attacks (commonly experienced as network probes and other "doorknob rattling" activities)4. To document the existing threat to an organization5. To act as quality control for security design and administration, especially of large and complex enterprises6. To provide useful information about intrusions that do take place, allowing improved diagnosis, recovery, and correction of causative factors