Linux Tech Tips

Introduction Config Server Firewall (or CSF) is a free and advanced firewall for most Linux distributions. In addition to the basic functionality of a firewall – filtering packets – CSF includes other security features, such as login/intrusion/flood detections. CSF includes UI integration for cPanel, DirectAdmin and Webmin, but this tutorial only covers the command line usage. CSF is able to recognize many attacks, such as port scans, SYN floods, and login brute force attacks on many services. It is configured to temporarily block clients who are detected to be attacking the cloud server. The full list of supported operating systems and features can be found on  ConfigServer's website . This tutorial is written for Debian based distro, such as Debian and Ubuntu but should work on RHEL/CentOS also. The commands should be executed with root permissions, by logging in as root, or initiating a root shell with the following command if sudo is installed: sudo su...

<< Part 2                                                                                                      Part 4 >> Hardening the Linux server - Part 3 Write firewall rules You can deny access to your server through your firewall. Ubuntu Server uses a firewall called Uncomplicated FireWall (UFW), which is actually a management tool for iptables. Iptables filters network packets based on a series of rules written by the system administrator. Iptables can be complicated for beginners, so UFW simplifies it. Using UFW can help you harden your server; but if you're truly interested in server security, learning how to write rules for iptables will let you fine-tune a server's security. To get started with...