How to turn off ICMP responses:
Windows Workstation
You can either install a personal firewall or in later versions of Windows use the native Windows firewall.
Windows Server
You can either install a local firewall application or in later versions of Windows use the native Windows firewall.
Alternatively use your network routers or firewalls to deny ICMP responses.
Linux Redhat 6.2
Use iptables as follows:
Login as root and enter the following command
iptables -A INPUT -p icmp -m state --state NEW -j DROP
Alternatively use ipchains:
Login as root and enter the following command
ipchains -A input -p icmp --icmp-type echo-request -j DENY