20

I want to disable ping response all the time on my Ubuntu operating system, the following commands work but only until the system reboots:

Ping off:

echo "1" > /proc/sys/net/ipv4/icmp_echo_ignore_all

Ping on: 

echo "0" > /proc/sys/net/ipv4/icmp_echo_ignore_all

How would I be able to leave echo off even after having rebooted my laptop?

Matthias Braun
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HardRebootHackerHD
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3 Answers3

27

How would I be able to leave echo off even when I am rebooting my laptop?

You can use one of the following three ways (as root):

Edit /etc/sysctl.conf

Add the following line to your /etc/sysctl.conf:

net.ipv4.icmp_echo_ignore_all=1

Then:

sysctl -p

Using iptables:

iptables -I INPUT -p icmp --icmp-type echo-request -j DROP

With cron

Run crontab -e as root, then add the following line:

@reboot echo "1" > /proc/sys/net/ipv4/icmp_echo_ignore_all

Start and enable the service:

systemctl start cron.service
systemctl enable cron.service
GAD3R
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0

Note that if you are using UFW and trying to apply the net.ipv4.icmp_echo_ignore_all setting in /etc/sysctl.conf, you may find that this does not have any effect after a reboot. In that case, have a look for the same setting in /etc/ufw/sysctl.conf and change it there.

Dan Parsonson
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0

In Debian-based Linux distributions that ship with UFW application firewall, you can block ICMP messages by adding the following rule to /etc/ufw/before.rules file:

-A ufw-before-input -p icmp --icmp-type echo-request -j DROP
Greenonline
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bl3ssedc0de
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