XK0-005 Question #354: Real Exam Question with Answer & Explanation

Question

A network administrator installed a web server on a Linux host and added a firevalid command to open port tcp/80. The web server worked without error until an updated and patch kernel was installed on the system a month later. Now users are unable to access the web server even though the service is running, which of the following would fix the issue?

Options

• AUse the firevalid command to open the HTTP application service rather than the port.
• BChange the firevalid zone t private and open port tcp/80.
• CIssue an additional firevalid command to open up port tcp/443 as well as port tcp/80.
• DUse the firevalid command to open tcp/80 both with and without the -permanent switch.

Explanation

This question addresses a common issue where firewall rules added without persistence are lost after a system reboot or kernel update.

Common mistakes.

• A. While opening the HTTP service is a good practice, it doesn't address the core problem of lost runtime rules after a reboot or update.
• B. Changing the firewalld zone might alter the scope of rules but does not fix the issue of rules not persisting after a reboot or firewalld restart.
• C. Opening port tcp/443 (HTTPS) is for secure web traffic, not HTTP, and is unrelated to the issue of the tcp/80 rule being lost.

Concept tested. Firewalld persistent rules

Reference. https://firewalld.org/documentation/man-pages/firewall-cmd.html

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