To disable all pings to your server, please follow these steps:
1. Login to your server as root via ssh and open up the /etc/sysctl.conf file using #vi /etc/sysctl.conf command.
2. At the end of the file, add net.ipv4.icmp_echo_ignore_all = 1 to disable ping. To enable use '0' instead of '1'.
3. Then restart the network using /etc/init.d/network reload
That's it!