In this lab, you'll view the effects of having Apache try to listen on an unauthorized port:

1. View the ports that SELinux allows the Apache web server daemon to use:

sudo semanage port -l | grep 'http'

2. Open the /etc/httpd/conf/httpd.conf file in your favorite text editor. Find the line that says Listen 80 and change it to Listen 82. Restart Apache by entering the following:

sudo systemctl restart httpd

3. View the error message you receive by entering:

sudo tail -20 /var/log/messages

4. Add port 82 to the list of authorized ports and restart Apache:

sudo semanage port -a 82 -t http_port_t -p tcp
sudo semanage port -l
sudo systemctl restart httpd

5. Delete the port that you just added:

sudo semanage -d 82 -t http_port_t -p tcp

6. Go back into the /etc/httpd/conf/httpd.conf file and change Listen 82 back to Listen 80. Restart the Apache daemon to return to normal operation.
7. End of lab.

Okay, you've seen how SELinux can protect you against various bad things, and how to troubleshoot things that go wrong. Let's turn our attention to AppArmor.