What can he used to set up a firewall on a Linux system? A. netstat B. route C. trace D. ipchains E. None of the above

The correct answer is: E. None of the above

The following are the tools that can be used to set up a firewall on a Linux system:

• iptables: iptables is a command-line tool that allows you to configure the Linux kernel’s netfilter firewall.
• ufw: ufw is a front-end for iptables that provides a more user-friendly interface.
• gufw: gufw is a graphical user interface for ufw.
• firewalld: firewalld is a complete firewall solution for Linux that provides a more flexible and powerful way to manage your firewall than iptables.

netstat, route, and trace are not tools that can be used to set up a firewall on a Linux system.