Enable/Disable ping in a server

To disable ping in the server, you can execute the following

root@amaziah [~]# echo "1" > /proc/sys/net/ipv4/icmp_echo_ignore_all

Now, if you want to re-enable it,

root@amaziah [~]# echo "0" > /proc/sys/net/ipv4/icmp_echo_ignore_all

Now to disable it permanently, you can edit /etc/sysctl.conf

root@amaziah [~]#vi /etc/sysctl.conf

edit the following line

net.ipv4.icmp_echo_ignore_all = 0

and replace the "0" with "1" ie.

net.ipv4.icmp_echo_ignore_all = 1

 then save and close the file.