Disabling ICMP

brianthegreat · 02-18-2006, 10:30 PM

Been digging around on the net looking for a way to disable ICMP and have not had any luck. Can anyone point me to a good resource for disabling ICMP. Had no trouble at all disabling ICMP on ym Fedora box.

macemoneta · 02-18-2006, 10:43 PM

It would be useful to know your configuration (is there a router in front of the system that is actually responding to ICMP?), your current distribution and release (not Fedora isn't specific enough), and what firewall software you are running (IPTABLES? Do you use a GUI/web front-end?).

brianthegreat · 02-18-2006, 11:16 PM

No router is involved just a GUI firewall.

Freemor · 02-18-2006, 11:45 PM

IPtables can block icmp quite effectively. Simply issueing a command similar to the one below would do a very effective job (at least for inbound icmp)

sudo iptables -A INPUT -p icmp -j DROP

Breaking it down...
we add (-A) an INPUT filter for protocol (-p) icmp and tell iptables to drop them all (-j DROP)

as you mentioned you are using a gui/frontend You'll need to figure out how to add the input filter to drop all icmp protocol packets. shouldn't be to difficult.

hope this helps
Freemor