Firewall Troubleshooting

30 minutes
  • 3 Learning Objectives

About this Hands-on Lab

In this learning activity, there is a fairly simple, but broken, firewall configuration. The firewall on `Server1` ( should be configured to permit web requests from `Client1` (

You will need to determine why the firewall isn’t working as intended, and resolve the issue.

Learning Objectives

Successfully complete this lab by achieving the following learning objectives:

Verify That the Issue Exists

Prior to beginning the troubleshooting, you should verify that the issue actually exists.

Attempt to curl the headers for from

$ curl -I

Resolve the Problem by Creating a New Zone

You can resolve this issue by creating a new zone, adding the http service to it, and designating as a source for the zone. Use these commands:

 [root@$host ~]# firewall-cmd --permanent --new-zone=api
 [root@$host ~]# firewall-cmd --reload
 [root@$host ~]# firewall-cmd --permanent --zone=api --add-service=http
 [root@$host ~]# firewall-cmd --permanent --zone=api --add-source=
 [root@$host ~]# firewall-cmd --reload
Verify That the Problem Is Resolved

From Client1 (, run:

curl -I

Additional Resources

A business unit is complaining that their host ( is unable to access the web API on They are asserting that a system administrator has already added the firewall rule necessary for these hosts to be able to communicate.

You will need to assess the current firewall configuration, and make the changes necessary that will permit port 80 requests from to, while still preserving the generic rule that blocks traffic.

What are Hands-on Labs

Hands-on Labs are real environments created by industry experts to help you learn. These environments help you gain knowledge and experience, practice without compromising your system, test without risk, destroy without fear, and let you learn from your mistakes. Hands-on Labs: practice your skills before delivering in the real world.

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