Firewall basics (ufw, iptables) in Linux CLI - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the primary purpose of a firewall in Linux?

A firewall controls incoming and outgoing network traffic to protect the system from unauthorized access and attacks.

beginner

What does ufw stand for and what is it used for?

ufw stands for Uncomplicated Firewall. It is a user-friendly tool to manage firewall rules on Linux systems.

beginner

How do you enable the firewall using ufw?

You enable the firewall by running the command: sudo ufw enable. This activates the firewall with the current rules.

intermediate

What is iptables used for in Linux?

iptables is a powerful command-line tool to configure the Linux kernel firewall, allowing detailed control over network traffic.

intermediate

How would you list all current iptables rules?

Use the command sudo iptables -L -v to list all current firewall rules with details.

Which command enables the firewall using ufw?

A sudo ufw enable

B sudo ufw start

C sudo iptables enable

D sudo firewall start

The correct command to enable ufw firewall is 'sudo ufw enable'.

What does the command sudo iptables -L do?

A Lists all current firewall rules

B Deletes all firewall rules

C Enables the firewall

D Disables the firewall

The command 'sudo iptables -L' lists all current firewall rules.

Which tool is simpler for beginners to manage firewall rules?

A iptables

B tcpdump

C netstat

D ufw

ufw is designed to be an uncomplicated and user-friendly firewall tool.

What is the default policy of ufw if not changed?

A Allow all outgoing traffic

B Allow all incoming traffic

C Deny all incoming traffic

D Deny all outgoing traffic

By default, ufw denies all incoming traffic and allows all outgoing traffic.

Which command adds a rule to allow SSH traffic using ufw?

A sudo iptables allow ssh

B sudo ufw allow 22

C sudo ufw block 22

D sudo iptables add ssh

The command 'sudo ufw allow 22' allows SSH traffic on port 22.

Explain how to enable and check the status of the firewall using ufw.

Think about commands to turn on ufw and how to see if it is active.

Describe the difference between ufw and iptables in managing Linux firewalls.

Consider which tool is simpler and which is more powerful.