Finding a Problem Caused by a Misconfiguration of SELinux and Troubleshooting the Issue

Install the troubleshooting tools:

sudo yum install -y setroubleshoot setools

After failed attempts to start the Apache web werver on port 9100, find the line in the log files to confirm SELinux is the core issue.

Using grep

grep httpd /var/log/audit/audit.log

Using Both tail and grep

tail -n 100 /var/log/audit/audit.log | grep -i httpd

Using tail

tail -f /var/log/audit/audit.log 

Watch the Log in Real Time, in Another Terminal

sudo systemctl start httpd 

Using ausearch

sudo ausearch -p <process id>

Look at the Auditor

sudo grep httpd /var/log/audit/audit.log | audit2why

Locate the port label for Apache web server and add the needed port. Afterward, restart the Apache web server.

1. List all the possible port labels and search the list for http:

   semanage port -l | grep -i http
   

2. Add port 9100 to the http_port_t label:

   semanage port -m -t http_port_t -p tcp 9100
   

1. Create a file:

   sudo touch /var/www/html/test 
   

2. View the context:

   ls -Z /var/www/html/
   

3. Change the context of the file:

   semanage fcontext -a -t httpd_sys_content_t /var/www/html/index.html
   

4. Reset the security context:

   restorecon -v /var/www/html/index.html