One of the basic functions of a Red Hat Enterprise Linux system administrator is to protect a Linux computer and a network from inside and outside attacks. RHEL includes a variety of tools that can help you establish a secure computing environment.
RHEL includes powerful tools for securing networks from outside attacks. As these tools work in different ways, they provide layers of security. The tcp_wrappers tools use /etc/hosts.allow and /etc/hosts.deny to secure services by host and user. With iptables at your disposal, you can create a firewall that can further protect your RHEL system. The firewall can include IP masquerading to hide the IP addresses of the computers inside your LAN. SELinux uses Access Control Lists to secure individual services in different ways.
The Security Level Configuration tool supports fine-grained configuration of host and network security using iptables. The SELinux Management Tool supports fine-grained control of SELinux targeted policies. The Setroubleshoot Browser can help diagnose SELinux-related problems and even suggest solutions.