If you want to block ping requests to your critical linux servers due to security concerns then do the following:

Edit the file /etc/sysctl.conf

[root@server~]# vim /etc/sysctl.conf
and look for this line:
net.ipv4.icmp_echo_ignore_all

and set its value qual to 1
NOTE: if you dont find net.ipv4.icmp_echo_ignore_all then simply added to the last line be sure the the value is equals to 1.
So make it look like this:
net.ipv4.icmp_echo_ignore_all = 1

After that, to make changes effective without rebooting run following command:
#sysctl -p

Posted in: Linux.
Last Modified: November 8, 2013

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