--- title: "ConfigServer Security & Firewall (CSF)" source: "https://docs.nexcess.com/hosting/security/firewall-management/configserver-security-firewall-csf/" description: "Harden your Linux server with CSF. Our guides show you how to install, configure, and manage this powerful firewall and security application." vertical: "Hosting" date: "2025-07-14" last_modified: "2026-07-29" --- # ConfigServer Security & Firewall (CSF) ConfigServer Security & Firewall (CSF) is a security application for Linux that provides a stateful packet inspection (SPI) firewall, intrusion detection, and other protective features. It is used to control access and protect the server from common attacks. CSF works by examining the state of network connections to filter traffic. It includes the Login Failure Daemon (LFD) process, which automatically blocks IP addresses that show signs of brute-force login attempts against server services. The firewall allows for granular control, such as blocking traffic from entire countries and limiting connection rates. CSF also integrates directly with control panels like cPanel and InterWorx. --- ConfigServer Security & Firewall Articles 10 results This collection of articles will guide you through the installation, configuration, and management of this essential security application. - ## [Adjusting LFD Notifications for Load Levels](https://docs.nexcess.com/hosting/security/firewall-management/configserver-security-firewall-csf/adjusting-lfd-notifications-for-load-levels/) LFD monitors server security and load levels. Adjust PT\_Load\_Level in WHM to prevent false positives by matching it to the server’s CPU cores. [Read more: Adjusting LFD Notifications for Load Levels](https://docs.nexcess.com/hosting/security/firewall-management/configserver-security-firewall-csf/adjusting-lfd-notifications-for-load-levels/) - ## [Allowing Port Access by IP Address in CSF](https://docs.nexcess.com/hosting/security/firewall-management/configserver-security-firewall-csf/allowing-port-access-by-ip-address-in-csf/) Each open firewall port is a potential vulnerability. It’s vital to keep all ports closed except for those essential for your server’s applications. [Read more: Allowing Port Access by IP Address in CSF](https://docs.nexcess.com/hosting/security/firewall-management/configserver-security-firewall-csf/allowing-port-access-by-ip-address-in-csf/) - ## [Backing Up Your CSF Firewall Configuration](https://docs.nexcess.com/hosting/security/firewall-management/configserver-security-firewall-csf/backing-up-your-csf-firewall-configuration/) Before modifying CSF firewall settings, backup the current configuration. It ensures site protection if changes lead to unexpected issues, aiding troubleshooting. [Read more: Backing Up Your CSF Firewall Configuration](https://docs.nexcess.com/hosting/security/firewall-management/configserver-security-firewall-csf/backing-up-your-csf-firewall-configuration/) - ## [Blocking Traffic by Country in the CSF Firewall](https://docs.nexcess.com/hosting/security/firewall-management/configserver-security-firewall-csf/blocking-traffic-by-country-in-the-csf-firewall/) Using CSF in WHM, filter and manage traffic by country. This helps with bandwidth, security, and content access but requires careful consideration. [Read more: Blocking Traffic by Country in the CSF Firewall](https://docs.nexcess.com/hosting/security/firewall-management/configserver-security-firewall-csf/blocking-traffic-by-country-in-the-csf-firewall/) - ## [CSF Country Blocking Dependency – Maxmind](https://docs.nexcess.com/hosting/security/firewall-management/configserver-security-firewall-csf/csf-country-blocking-dependency-maxmind/) Learn about changes to CSF Country Blocking requiring that a key is obtained. Then, there is a value in /etc/csf/csf.conf that needs to be updated with the free license key. [Read more: CSF Country Blocking Dependency – Maxmind](https://docs.nexcess.com/hosting/security/firewall-management/configserver-security-firewall-csf/csf-country-blocking-dependency-maxmind/) - ## [Getting Started with Configserver’s ModSecurity Control Plugin](https://docs.nexcess.com/hosting/security/firewall-management/configserver-security-firewall-csf/getting-started-with-configservers-modsecurity-control-plugin/) Use the ConfigServer ModSecurity Control (CMC) plugin in WHM to whitelist specific rules for a secure yet smooth-running site. Configure it with this article’s guidance. [Read more: Getting Started with Configserver’s ModSecurity Control Plugin](https://docs.nexcess.com/hosting/security/firewall-management/configserver-security-firewall-csf/getting-started-with-configservers-modsecurity-control-plugin/) - ## [Installing Configserver’s ModSecurity Control Plugin on Your Server](https://docs.nexcess.com/hosting/security/firewall-management/configserver-security-firewall-csf/installing-configservers-modsecurity-control-plugin-on-your-server/) Protect your web apps using ModSecurity WAF. Learn how to verify your Apache installation, install rules, and add the ConfigServer CMC plugin to WHM. [Read more: Installing Configserver’s ModSecurity Control Plugin on Your Server](https://docs.nexcess.com/hosting/security/firewall-management/configserver-security-firewall-csf/installing-configservers-modsecurity-control-plugin-on-your-server/) - ## [Restoring CSF Firewall Configuration from a Backup](https://docs.nexcess.com/hosting/security/firewall-management/configserver-security-firewall-csf/restoring-csf-firewall-configuration-from-a-backup/) Protect your server by reverting unwanted changes. Learn how to safely restore your CSF firewall configuration from a backup in WHM’s Firewall Profiles. [Read more: Restoring CSF Firewall Configuration from a Backup](https://docs.nexcess.com/hosting/security/firewall-management/configserver-security-firewall-csf/restoring-csf-firewall-configuration-from-a-backup/) 1[2](?query-0-page=2) [Next Page](/hosting/security/firewall-management/configserver-security-firewall-csf?query-0-page=2)