For those of you who are new to configuring Red Hat Enterprise Linux systems you may find some level of difficulty configuring services such as httpd, samba, e-mail, etc. The most frustration comes from configuring a service correctly however not being able to connect from another PC. For example you may have spent hours configuring an Apache web server however are unable to connect to the site from another computer.
Most likely the problem can be traced back to not having SELinux or the firewall (iptables) configured correctly. There are guides out there for configuring services that instruct you to disable the firewall or to disable SELinux. I would highly recommend that you NOT do this disable SELinux or the firewall! This is a double emphasis for those configuring Red Hat Enterprise Linux (RHEL) servers for a production environment as disabling those security settings could place your job in jeopardy. Disabling SELinux and the firewall will make it easier to configure your services however doing so would expose your system to security breeches. Disabling the firewall would allow incoming connections on virtually any port and disabling SELinux would expose the file system to further manipulation.
If you’re going to be using RHEL in a production environment take the time to understand which ports are used by your application so that you may open the appropriate ports in the firewall and set the appropriate SELinux contexts instead of disabling these security features.
As always I’d like to hear from you so please post your opinions regarding this topic.