How to install CSF Firewall (ConfigServer Security & Firewall)

A Stateful Packet Inspection (SPI) firewall, Login/Intrusion Detection and Security application for Linux servers.

**Supported and Tested Operating Systems**
RedHat v7.3, v8.0, v9.0
RedHat Enterprise v3, v4, v5, v6 (32/64 bit)
CentOS v3, v4, v5, v6 (32/64 bit) Fedora Core v1 to v16(32/64 bit) *Gentoo CouldLinux (based on CentOS/RHEL) *openSUSE v10, v11 *Debian v3.1, v4, v5, v6 *Ubuntu v6.06 LTS, v8.10, v9.10, v10.04 LTS, v10.10 *Mandriva 2009, 2010 *Slackware v12.2 (* may require custom regex patterns for some functions)****
**Supported and Tested Virtual Servers** **Virtuozzo **OpenVZ VMware UML MS Virtual Server VirtualBox (** requires correct iptables configuration on host server)
**CSF supports Cpanel, DirectAdmin and Webmin**
## CSF Features:
  • Straight-forward SPI iptables firewall script
  • Daemon process that checks for login authentication failures for: - Courier imap, Dovecot, uw-imap, Kerio
  • openSSH
  • cPanel, WHM, Webmail (cPanel servers only)
  • Pure-ftpd, vsftpd, Proftpd
  • Password protected web pages (htpasswd)
  • Mod_security failures (v1 and v2)
  • Suhosin failures
  • Exim SMTP AUTH
  • Custom login failures with separate log file and regular expression matching
  • POP3/IMAP login tracking to enforce logins per hour
  • SSH login notification
  • SU login notification
  • Excessive connection blocking
  • UI Integration for cPanel, DirectAdmin and Webmin
  • Easy upgrade between versions from within cPanel/WHM, DirectAdmin or Webmin
  • Easy upgrade between versions from shell
  • Pre-configured to work on a cPanel server with all the standard cPanel ports open
  • Pre-configured to work on a DirectAdmin server with all the standard DirectAdmin ports open
  • Auto-configures the SSH port if it’s non-standard on installation
  • Block traffic on unused server IP addresses – helps reduce the risk to your server
  • Alert when end-user scripts sending excessive emails per hour – for identifying spamming scripts
  • Suspicious process reporting – reports potential exploits running on the server
  • Excessive user processes reporting
  • Excessive user process usage reporting and optional termination
  • Suspicious file reporting – reports potential exploit files in /tmp and similar directories
  • Directory and file watching – reports if a watched directory or a file changes
  • Block traffic on the DShield Block List and the Spamhaus DROP List
  • BOGON packet protection
  • Pre-configured settings for Low, Medium or High firewall security (cPanel servers only)
  • Works with multiple ethernet devices
  • Server Security Check – Performs a basic security and settings check on the server (via cPanel/DirectAdmin/Webmin UI)
  • Allow Dynamic DNS IP addresses – always allow your IP address even if it changes whenever you connect to the internet
  • Alert sent if server load average remains high for a specified length of time
  • mod_security log reporting (if installed)
  • Email relay tracking – tracks all email sent through the server and issues alerts for excessive usage (cPanel servers only)
  • IDS (Intrusion Detection System) – the last line of detection alerts you to changes to system and application binaries
  • SYN Flood protection
  • Ping of death protection
  • Port Scan tracking and blocking
  • Permanent and Temporary (with TTL) IP blocking
  • Exploit checks
  • Account modification tracking – sends alerts if an account entry is modified, e.g. if the password is changed or the login shell
  • Shared syslog aware
  • Messenger Service – Allows you to redirect connection requests from blocked IP addresses to preconfigured text and html pages to inform the visitor that they have been blocked in the firewall. This can be particularly useful for those with a large user base and help process support requests more efficiently
  • Country Code blocking – Allows you to deny or allow access by ISO Country Code
  • Port Flooding Detection – Per IP, per Port connection flooding detection and mitigation to help block DOS attacks
  • DirectAdmin UI integration
  • Updated Webmin UI integration
  • WHM root access notification (cPanel servers only)
  • New in v5: lfd Clustering – allows IP address blocks to be automatically propagated around a group of servers running lfd. It allows allows cluster-wide allows, removals and configuration changes
  • New in v5: Quick start csf – deferred startup by lfd for servers with large block and/or allow lists
  • New in v5: Distributed Login Failure Attack detection
  • New in v5: Temporary IP allows (with TTL)
  • New in v5: IPv6 Support with ip6tables
  • New in v5: Integrated UI – no need for a separate Control Panel or Apache to use the csf configuration
  • New in v5: Integrated support for cse within the Integrated UI
  • New in v5: cPanel Reseller access to per reseller configurable options Unblock, Deny, Allow and Search IP address blocks
  • …lots more!

CSF Installation:

Basic commands to install CSF

rm -fv csf.tgz wget tar -xzf csf.tgz cd csf sh

For more information, please read official guidance (install.txt)

With Cpanel, after installing you log in to WHM and you can see ConfigServer Security&Firewall line under Plugins menu.

I recommend you use “Check server security” function first (Server Security Information section) and follow CSF guidelines to secure your server (VPS/Dedicated server). Then you can Turn off CSF TEST MODE.

You may be hard to understand some points when you follow CSF guidelines, I will try my best to show you how next time. Thank you.

CSF official website:

Written on 11 April 2012

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