Security Basics mailing list archives
Re: Removing ping/icmp from a network
From: Jason <securitux () gmail com>
Date: Thu, 27 Mar 2008 14:52:28 -0400
ICMP is allowed throughout most Internet routers, if you can trace all the way to the hop before the firewall, then you have narrowed down where the issue is.
From there, what about network analysis and application monitoring
tools? What about tcpdump, ethereal, etc? Can that not be used that to check network and server latency / response times on a standard web request? We have a customer in Australia who's ISP blocks all ICMP to and from their CPE routers. We seem to get along just fine. Web site is down or is slow and the router before the CPE is responding, dump the packets, look at the timestamps and see what's going on. IP packet traces spit back latency just fine with or without ICMP. Problem inside the CPE? Use remote management tools over a VPN to troubleshoot further (if you manage the server of course). Reputation is not going to change based on whether ICMP is allowed or not... if the web site is down its down, clients aren't going to care if they can ping it or not if they can't access their data through SSL or whichever protocol either way. "Well I can't do my job, but this is a stable server because I can ping it". Plus, if you absolutely must have ICMP to troubleshoot from the Internet, firewall rules can be used to narrow the source and destination as someone else in this thread suggested. I may have given too much of a blanket statement when saying no ICMP from the Internet at all, I should have said no open ICMP. Controlled ICMP through a firewall with proper rules should be good. I don't consider MS's site unreliable just because I, or anyone on the Internet for that matter, can't ping it. -J On Thu, Mar 27, 2008 at 1:09 PM, Mark Owen <mr.markowen () gmail com> wrote:
On Thu, Mar 27, 2008 at 12:25 PM, Jason <securitux () gmail com> wrote: *snip* > The idea is to limit your Internet footprint to make it as difficult > as possible for an attacker. There is no need for a web server to > respond to ping from the Internet for example. It is very critical that your web server responds to ICMP on the Internet. If you go out of the way and ignore essential protocols for IP over a public network, you're just going to create a headache for all of us. Without ICMP, it is very difficult for us to determine where a problem exists when our clients complain about slow load times or inaccessibility to your website. No ICMP means no basic trace routing, no basic latency checks, and no basic error reporting. So even if the problem is somewhere in our infrastructure that limits or prevents access to your site, you're going to get the blame and bad reputation of an unstable server. If it doesn't respond to ping, and can't be traced, its not our fault that our client can't access your site, it's yours. -- Mark Owen
Current thread:
- RE: Removing ping/icmp from a network, (continued)
- RE: Removing ping/icmp from a network Strykar (Mar 26)
- RE: Removing ping/icmp from a network Murda Mcloud (Mar 27)
- RE: Removing ping/icmp from a network Murda Mcloud (Mar 27)
- Re: Removing ping/icmp from a network Jason Thompson (Mar 26)
- RE: Removing ping/icmp from a network Worrell, Brian (Mar 26)
- Re: Removing ping/icmp from a network Ansgar -59cobalt- Wiechers (Mar 26)
- RE: Removing ping/icmp from a network Craig Wright (Mar 26)
- Re: Removing ping/icmp from a network Jason (Mar 27)
- Re: Removing ping/icmp from a network Mark Owen (Mar 27)
- R: Removing ping/icmp from a network Vega - Brunello Ivan (Mar 27)
- Re: Removing ping/icmp from a network Jason (Mar 27)
- Re: Removing ping/icmp from a network Michael Painter (Mar 27)
- Re: Removing ping/icmp from a network Razi Shaban (Mar 28)
- Re: Removing ping/icmp from a network Michael Painter (Mar 28)
- Re: Removing ping/icmp from a network Ansgar -59cobalt- Wiechers (Mar 28)
- Re: Removing ping/icmp from a network Michael Painter (Mar 31)
- RE: Removing ping/icmp from a network Ric Messier (Mar 28)
- RE: Removing ping/icmp from a network Adewale, Akin (IT Services - Infosec Team) (Mar 28)
- RE: Removing ping/icmp from a network Strykar (Mar 26)
- RE: Removing ping/icmp from a network Craig Wright (Mar 28)
- Re: Removing ping/icmp from a network Ansgar -59cobalt- Wiechers (Mar 28)
- Re: Removing ping/icmp from a network Jason (Mar 28)