sysctl is an interface that allows you to make changes to a running Linux kernel. With /etc/sysctl.conf you can configure various Linux networking and system settings such as:

• Limit network-transmitted configuration for IPv4
• Limit network-transmitted configuration for IPv6
• Turn on execshield protection
• Prevent against the common ‘syn flood attack’
• Turn on source IP address verification
• Prevents a cracker from using a spoofing attack against the IP address of the server.
• Logs several types of suspicious packets, such as spoofed packets, source-routed packets, and redirects.

Harden the system using sysctl

View sysctl values