|| what is ping
please take a look this
|| how to disable icmp / ping respond
# echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all
if you want to save permanently
# vi /etc/sysctl.conf ; add this line: net.ipv4.conf.icmp_echo_ignore_all = 1
|| how to enable icmp / ping respond on linux
# echo 0 > /proc/sys/net/ipv4/icmp_echo_ignore_all
or
# vi /etc/sysctl.conf ; edit / remove this line like: net.ipv4.conf.icmp_echo_ignore_all = 0