Many malicious attacks begin with a ping scan. Disabling ICMP echo requests prevents your system’s discovery with a ping.
As superuser, add the following lines to /etc/sysctl.conf
net.ipv4.icmp_echo_ignore_broadcasts = 1
net.ipv4.icmp_echo_ignore_all = 1
Then run the following command to cause the change to take effect immediately:
This change will persist following a reboot.