What does the /etc/sysctl.conf file do in a Linux system?

The /etc/sysctl.conf file is specifically designed for configuring kernel parameters at runtime on a Linux system. It allows system administrators to modify various aspects of the operating system such as networking, memory management, and performance tuning. By setting parameters in this file, administrators can enable or disable certain features, adjust system performance, and enhance security behaviors of the kernel.

For example, through this file, you can set parameters like the maximum size of the TCP window, how the system handles syn flood attacks, or even how memory is allocated. Upon boot, the settings defined in this configuration file are applied, ensuring that the specified parameters persist across reboots, thus allowing for consistent system behavior.

While other files and configurations manage user permissions, file system inodes, and even DNS servers, /etc/sysctl.conf's focus is solely on kernel parameter adjustments, making it vital for fine-tuning system and network performance in a Linux environment.