GIAC Certified Forensic Analyst (GCFA) — Question 45

You work as a Network Administrator for Perfect Solutions Inc. The company has a Linux-based network. You are creating a user account by using the USERADD command. Which of the following entries cannot be used for specifying a user ID?
Each correct answer represents a complete solution. Choose all that apply.

Answer options

• A. 0
• B. 99
• C. 100
• D. -1

Correct answer: A, B, D

Explanation

The user ID of 0 is reserved for the root user, making it invalid for general accounts. The ID -1 is also invalid as user IDs must be non-negative integers. However, 99 and 100 are valid user IDs and can be used without issue.