Penetration Testing mailing list archives
Re: DENY x REJECT
From: Fyodor <fyodor () insecure org>
Date: Thu, 4 Oct 2001 15:33:03 -0700
On Wed, Oct 03, 2001 at 12:52:51PM -0300, Rosenau wrote:
Nmap seems to report boths cases simply as "filtered". Actually, both cases are filtered, but when you receive a ICMP, you can be sure that the port is really filtered. If you do not receive nothing, the port could be filtered, or packets could have been lost...
For what it is worth, Nmap always retries ports that do not respond. It only marks them "filtered" after multiple probes fail to elicit any response. If lost packets are detected (for example if Nmap receives a response to the second probe but not the first one), then the number of retries is increased dramatically. Thus it is unlikely that an open port will be mislabeled "filtered" because of a few dropped packets. That being said, I agree that knowing the source of ICMP error messages is handy and I am hoping to add that to the XML output format at some point. If you want it really soon, you are welcome to make the (relatively simple) changes yourself. That is the beauty of open source! If you send me your patches, I will consider them for the core Nmap tree so that everyone can benefit from them. Cheers, Fyodor http://www.insecure.org/ ---------------------------------------------------------------------------- This list is provided by the SecurityFocus Security Intelligence Alert (SIA) Service. For more information on SecurityFocus' SIA service which automatically alerts you to the latest security vulnerabilities please see: https://alerts.securityfocus.com/
Current thread:
- DENY x REJECT Rosenau (Oct 04)
- Re: DENY x REJECT R. DuFresne (Oct 04)
- Re: DENY x REJECT Fyodor (Oct 04)
- RE: DENY x REJECT Ofir Arkin (Oct 09)
- Re: DENY x REJECT niceshorts (Oct 09)
- RE: DENY x REJECT Ofir Arkin (Oct 10)
- Re: DENY x REJECT niceshorts (Oct 10)
- Re: DENY x REJECT niceshorts (Oct 09)
- <Possible follow-ups>
- RE: DENY x REJECT Frank Knobbe (Oct 04)
- Fw: DENY x REJECT Mehmet Murat Gunsay (Oct 05)