Introduction
In 2025, many server administrators and hosting companies have experienced problems with CSF (ConfigServer Security & Firewall) in WHM/cPanel, a popular tool for managing security on Linux servers. This situation has caused confusion and frustration among users, who relied on CSF to protect their servers. In this blog, we will explain the reasons behind this problem and the new features that are affecting its operation in 2025.
What is CSF and why is it used with WHM/cPanel?
CSF is a firewall and security tool widely used on servers running WHM/cPanel. It allows server administrators to protect their systems against external threats, block malicious IP addresses, manage ports and apply custom security policies. It is especially popular for its easy integration with WHM/cPanel, making it a favorite choice for those who manage shared hosting or dedicated servers.
The WHM/cPanel Upgrade and its Impact on CSF
In 2025, cPanel, the platform that WHM uses for server management, released a series of major updates to improve security, performance and compatibility. However, these updates also included changes to the way firewall rules and network configurations are managed.
One of the most significant changes was the integration of new system-level security policies that conflicted with CSF's firewall rules. The cPanel upgrades introduced a new structure for security management and DDoS protection, causing some of CSF's key functions to stop working as expected.
Technical Reasons Behind CSF Incompatibility
Some of the main reasons that caused the incompatibility between CSF and the latest versions of WHM/cPanel include:
- Changes in network libraries: New updates to cPanel changed certain network libraries that CSF uses to manage inbound and outbound connections. This caused CSF to stop working correctly on some servers, generating errors when trying to apply firewall rules.
- Conflicts with the integrated safety module: cPanel introduced a more robust security module that now takes control of some functions previously managed by CSF. This included open port management and malicious IP blocking, which led to configuration conflicts.
- Problems with automatic updates: CSF and cPanel have automatic update mechanisms that do not always synchronize well. When applying security updates, CSF sometimes fails to keep up with new cPanel configurations, leading to disruption of its functionality.
What's New in cPanel Security Affecting CSF?
With the advent of new security threats and the need to better protect servers, cPanel introduced several enhancements that are now managing aspects that were previously the responsibility of CSF. These new features include:
- Integrated advanced firewall: cPanel implemented its own advanced firewall with automatic protection against DDoS attacks, intrusions and vulnerability scans. This firewall now handles most of the functions previously performed by CSF, making the latter unnecessary in many cases.
- Improved detection of malware and brute force attacks: cPanel now has enhanced tools to detect and prevent brute-force attacks and malware, which detracts from CSF's functionality in this area.
- Enhanced multi-factor authentication (MFA): cPanel has also introduced stronger multi-factor authentication in its administration panel, making the additional control that CSF offered in terms of access protection unnecessary.
Alternatives and Solutions for Server Administrators
Although CSF no longer works properly in the latest WHM/cPanel releases, there are several alternatives for server administrators to consider:
- cPanel Firewall: Use the new security features built into cPanel, such as its advanced firewall and DDoS protection. While not as flexible as CSF, it offers robust protection and is easier to manage within the cPanel environment.
- Configuration of additional tools: Administrators can consider using tools such as Imunify360, which also offers protection against malware, DDoS attacks and vulnerability scans, complementing the firewall functions of cPanel.
- Manual review of firewall configurations: If you still prefer to use CSF, some server administrators are manually reconfiguring it by disabling the firewall options built into cPanel and adjusting CSF to work in a custom environment.
Conclusion
The end of CSF in WHM/cPanel in 2025 is not the end of server protection, but rather a sign of how hosting platforms are evolving to offer more integrated and robust security solutions. While many users have experienced problems with the tool, cPanel's new security features and the ability to adopt alternatives such as Imunify360 offer effective solutions to protect servers.
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