Practice for the GIAC Security Essentials (GSEC) exam with 14 exam-style practice questions, instant answer reveals, and concise explanations of every correct answer. Topics include: Which of the following Linux security commands operates as a firewall?. Follow @CertPunch and visit certpunch.com for more certification practice exams and study content.
Prefer hands-on? Take this round as an interactive practice test — answer every question, get instant feedback, and see your score: Start the GSEC practice test →
What you will practice
- Which of the following Linux security commands operates as a firewall?
- Which of the following is NOT a Linux command use to monitor or manage processes?
- What is the most important patching or upgrading best practice for Linux and Windows systems?
- Which of the following is NOT a feature or function that can be set or defined by the Linux passwd command?
- How would a user determine their IP address and subnet mask on a Linux system?
- What is the command or tool on Linux that can be used to perform network sniffing and packet capturing?
Answers and explanations
Tap a question to expand the answer and the exam reasoning. Try to commit to your own pick first.
Q1. Which of the following Linux security commands operates as a firewall?
Answer: A. A) iptables
The iptables utility functions as the default command-line firewall for Linux, filtering network traffic based on defined rule chains. Distractors fail because fsck repairs filesystems, nc handles network connections, and busybox provides tools.
Q2. Which of the following is NOT a Linux command use to monitor or manage processes?
Answer: B. B) grep
The grep command searches text using regular expressions and does not directly monitor or manage system processes. On the exam, remember that top displays active processes, while kill terminates them by their ID.
Q3. What is the most important patching or upgrading best practice for Linux and Windows systems?
Answer: D. D) Avoid installing new updates on production systems.
The most critical patching practice is never deploying new updates directly on production systems without prior testing. Always validate patches in a test environment first to prevent unexpected downtime or security regressions.
Q4. Which of the following is NOT a feature or function that can be set or defined by the Linux passwd command?
Answer: D. D) Set account lockout policy.
The passwd command manages passwords and aging policies but cannot configure account lockout thresholds. Linux achieves account lockout functionality natively through pluggable authentication modules, rather than the standard passwd utility.
Q5. How would a user determine their IP address and subnet mask on a Linux system?
Answer: D. D) Use the ifconfig command.
The ifconfig command displays IP addresses and subnet masks on Linux systems. While ipconfig is a Windows command, ifconfig is the classic Linux equivalent you need to know for the exam.
Q6. What is the command or tool on Linux that can be used to perform network sniffing and packet capturing?
Answer: D. D) tcpdump
Tcpdump is a command-line packet analyzer that captures network traffic for sniffing purposes. While nmap and hping3 are used for network discovery and scanning, tcpdump specifically collects raw packets.
Q7. Which of the following is NOT a Linux command?
Answer: D. D) cls
The cls command is a Windows utility used to clear the screen, not a Linux command. The Linux equivalent is clear, while commands like ls and chmod are native to Linux systems.
Q8. Why is the rm -rf / command dangerous to run when logged on as root in Linux?
Answer: D. D) It deletes all possible files.
Executing rm -rf / as root recursively deletes every file on the system, destroying the operating system. The rm command removes files, the dash r makes it recursive, and the slash targets root.
Q9. Why is it often necessary to prefix an executable name with ./ for it to launch from a Linux terminal prompt?
Answer: D. D) The current folder is not defined in the PATH environmental variable.
The current folder is typically excluded from the PATH environmental variable to prevent malicious scripts from running accidentally. Using the dot slash prefix explicitly tells the system to execute the file locally.
Q10. What is required for a user to be able to use the chmod command on a file object in Linux to change access permissions? (Choose two. Each correct option is a separate solution.)
Answer: A,B. A) Have ownership of the file. || B) Be the root.
To modify file permissions using chmod, you must either be the file owner or have root privileges. Standard users cannot change permissions for files they do not own without proper authorization.
Q11. When setting up or configuring Linux just after installation, which of the following is NOT a recommended activity?
Answer: C. C) Define hard coded mappings of all domain names to 127.0.0.1 in the /etc/hosts file.
Hardcoding all domain names to the loopback IP address in the hosts file breaks name resolution and prevents normal network access. Setting the hostname, verifying memory, and configuring the timezone are standard post-installation tasks.
Q12. How can a user launch applications as the root without knowing the root password in Linux? (Choose two.)
Answer: B,D. B) Use suid. || D) Use sudo.
Configuring sudo access and setting the SUID bit both allow a binary to run with root privileges without requiring the root password. Remember that chmod is used to change permissions, while run as is a Windows concept.
Q13. Which of the following commands is NOT a means to restart a Linux service?
Answer: B. B) process <daemon> reset
The phrase process daemon reset is not a valid Linux command for managing services. Valid historical methods include using the service command or calling the init.d scripts directly with start or stop arguments.
Q14. For which of the following devices can Linux be used as an operating system? (Choose all that apply.)
Answer: A,B,C,D. A) Servers || B) Client portable computers || C) Smart phones || D) Smart TVs
Linux is a highly versatile kernel that runs on a vast array of hardware, including servers, laptops, smartphones, and smart TVs. For the exam, recognize that Linux is not limited to traditional desktop or server environments.
More GSEC drills and other practice exams are on @CertPunch. New rounds drop every few days at certpunch.com.