Turning off ping responses in RHEL5

There are so many processes to block ICMP ping in RHEL5. This process is about “How to block ICMP packets through Kernel Configuration?”

Persistent system configuration : sysctl -a (Lists all current kernel settings)
Settings a /proc value dynamically : sysctl –w (Kernel settings)
Reloading Kernel settings : sysctl –p

To block ICMP packets : /proc/sys/net/ipv4/icmp_echo_ignore_all
: Search for sysctl –a grep net।ipv4।icmp_echo_ignore_all

set the value
Sysctl –w net.ipv4.icmp_echo_ignore_all=1

Ping “IPAddress”
PING 192.168.x.x (192.168.x.x) 56(84) bytes of data.
No response...

Sysctl –w net.ipv4.icmp_echo_ignore_all=0

PING 192.168.x.x (192.168.x.x) 56(84) bytes of data.
64 bytes from 192.168.x.x: icmp_seq=1 ttl=64 time=0.889 ms

--- 192.168.x.x ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4002ms
rtt min/avg/max/mdev = 0.079/0.261/0.889/0.315 ms

If you want to make this persistent across reboots..!

Edit /etc/sysctl.conf
Search for net.ipv4.icmp_echo_ignore_all
Change the value to 1 or 0 as per your requirement.
Update your system kernel settings : Sysctl –p
Shutdown –r now

Ping “IPAddress”
PING 192.168.x.x (192.168.x.x) 56(84) bytes of data.
No response ...