Block ICMP ping in Redhat 9

dsschanze · 07-24-2006, 02:26 PM

Hi,
I am setting up an HTTP server on Redhat 9. How do I set my system to block ICMP pings? I would like to be able to set this option as I have been a hacking victim a few times already and would like to add as much security as possible.

Thanks,
Derek

cachemonet · 07-24-2006, 03:40 PM

iptables -A INPUT -p ICMP -j DROP

This is easily defeated with a syn scan with nmap. You still need to continue to read security bulletins. Most basic script kiddies will still find your system if they want to.

gilead · 07-24-2006, 03:54 PM

It's true that disabling ping doesn't stop people finding your box. For all I know you have a good reason, so another way to do it is to edit /etc/sysctl.conf and add the following line, then re-read the settings with sysctl -p /etc/sysctl.conf

Code:

net.ipv4.icmp_echo_ignore_all = 1

dsschanze · 07-24-2006, 04:40 PM

Thanks very much!

-Derek

win32sux · 07-24-2006, 05:21 PM

if you have your INPUT policy set to DROP (you should), then you wouldn't need to take any of these measures to block PINGs... if your box is exclusively an HTTP/HTTPS server, then really you only need to accept TCP packets to ports 80 and 443 - no ICMP at all...