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This document is for a previous release of cPanel & WHM. To view our latest documentation, visit our Home page.

For cPanel & WHM 11.40

(Home >> Security Center >> Shell Fork Bomb Protection)


This feature will prevent users with terminal access (SSH or Telnet) who attempt to use up the system’s resources and potentially crash your web server with a malicious attack known as a fork bomb.

Fork bombs start a cascade of small processes that duplicate themselves until the server’s resources are depleted.

How to configure shell fork bomb protection

To enable or disable shell fork bomb protection:

  • Click Enable Protection or Disable Protection.

After you have enabled shell fork bomb protection, the following limits are available to better protect the server:


200000-cLimits the maximum size of core files that are created.
200000-dLimits the maximum size of a process's data segment.
200000-mLimits the maximum resident set size.
100-nLimits the maximum number of open-file descriptors.
8192-sLimits the maximum stack size.
35-uLimits the maximum number of processes available to a single user.
Unlimited-vThe amount of virtual memory available for the process.

The -u option limits bash shell users (default for cPanel users) to 35 processes each.