Discuss CompTIA XK0-006 Exam Topic 2 Question 3

A Linux administrator is testing a web application on a laboratory service and needs to temporarily allow DNS and HTTP/HTTPS traffic from the internal network. Which of the following commands will accomplish this task?

Afirewalld -- add-service=dns, http,https -- zone=internal

Biptables -- enable-service='dns|http|https' -- zone=internal

Cfirewall-cmd --add-service={dns, http, https} --zone=internal

Dsystemctl mask firewalld --for={dns, http, https} --zone=internal

Suggested Answer: C

Comprehensive and Detailed Explanation From Exact Extract:

The correct way to temporarily allow specific services in a particular zone with firewalld is to use firewall-cmd --add-service=service --zone=zone. Multiple services can be specified in curly braces and separated by commas. The correct syntax is:

bash

CopyEdit

firewall-cmd --add-service={dns,http,https} --zone=internal

This command will allow DNS (port 53), HTTP (port 80), and HTTPS (port 443) through the firewall for the 'internal' zone temporarily (for the current runtime session).

Other options:

A . The command syntax is incorrect; firewalld is a service, not a command-line tool.

B . iptables does not use the --enable-service flag, nor does it have zones in this way.

D . systemctl mask disables services, and the rest of the command is invalid.

CompTIA Linux+ Study Guide: Exam XK0-006, Sybex, Chapter 9: 'Networking', Section: 'Managing Firewalls with firewalld'

CompTIA Linux+ XK0-006 Objectives, Domain 2.0: Networking

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12 comments · newest first

Arlette 3 months ago

Definitely C! It’s clear and straightforward for allowing those services.

Edward 3 months ago

I feel like A could work too, but I’m not sure about the syntax.

Tricia 3 months ago

I think option C is the right choice. It’s the correct syntax for firewall-cmd.

Han 3 months ago

Isn't D just masking the service instead of allowing traffic?

Marylou 3 months ago

Definitely C, I've used it before with no issues.

Regenia 4 months ago

Wait, can you really use firewalld like that?

Alex 5 months ago

I think A is better, more straightforward.

Lashon 5 months ago

C is the right command for that!

Latrice 6 months ago

I definitely remember that you can't mask services with systemctl like option D suggests, so that one is definitely out.

Elly 6 months ago

I feel like I might have seen a question similar to this in our study group, but I can't recall if it was about iptables or firewalld.

Jeanice 6 months ago

I remember practicing with firewall-cmd commands, and I think option C looks familiar. It seems to be the right format for adding services to a zone.

Heike 7 months ago

I think the command should be related to firewalld since it's commonly used in modern Linux systems, but I'm not sure about the exact syntax.

CompTIA XK0-006 Exam - Topic 2 Question 3 Discussion