System Variables

July 2016 ยท 1 minute read

Change at run time

sysctl can be used to read and tune kernel parameters at run time and changes will not be available after reboot.

  • Display current values: sysctl -a
  • Show value: sysctl net.ipv4.icmp_echo_ignore_all
  • Change values: sudo sysctl net.ipv4.icmp_echo_ignore_all=0

Make changes persistent

vi /etc/sysctl.conf

net.ipv4.icmp_echo_ignore_all=0 # 0 enable respond to ping, 1 disable respond to ping

sysctl -p to apply changes now. Check if your changes applied for example, sysctl net.ipv4.icmp_echo_ignore_all