Nmap Development mailing list archives
Re: ICMP Port Unreachable in Host Discovery
From: Kris Katterjohn <katterjohn () gmail com>
Date: Thu, 14 Jun 2007 15:58:50 -0500
Will Cladek wrote:
Kris, The host can be pinged as well, but you're right, there's no way of knowing for sure if it's the host or an external firewall on its behalf. It does seem odd not to just be using a RST or simply ignoring it completely. The thing that drew my attention to this is that normally I throw in a -PE flag to do a ping as well, and even though the host is pingable, occasionally the scan will just end and say the host is down. I haven't been able to recreate this is a controlled fashion, or else *that* would be what I'd post about. Maybe the host is just being inconsistent in replying to echo requests. I was just kind of hoping changing this ICMP port unreachable behavior would be a simpler solution. I guess I'll just wait and try to recreate the original situation and try to post about that. -Will
Hey, A couple of things: * Nmap has a --packet-trace option that might simplify your testing so you don't have to use tcpdump (unless tcpdump offers more information for your particular test). * You might also want to experiment with this host using the timing options (-T). Some hosts respond differently based on time, so slowing it down (like -T2) can affect things. But be warned, -T2 can take a while, so you should probably just use it separately for this host if you're going to be scanning more than just a few. Well, I hope that helps you. Thanks, Kris Katterjohn _______________________________________________ Sent through the nmap-dev mailing list http://cgi.insecure.org/mailman/listinfo/nmap-dev Archived at http://SecLists.Org
Current thread:
- ICMP Port Unreachable in Host Discovery Will Cladek (Jun 14)
- Re: ICMP Port Unreachable in Host Discovery Kris Katterjohn (Jun 14)
- Re: ICMP Port Unreachable in Host Discovery Will Cladek (Jun 14)
- Re: ICMP Port Unreachable in Host Discovery Kris Katterjohn (Jun 14)
- Re: ICMP Port Unreachable in Host Discovery Brett Cunningham (Jun 15)
- Re: ICMP Port Unreachable in Host Discovery Will Cladek (Jun 14)
- Re: ICMP Port Unreachable in Host Discovery Kris Katterjohn (Jun 14)