Nmap Development mailing list archives
RE: NSE loop issue with filtered ports
From: "Thomas Buchanan" <TBuchanan () thecompassgrp net>
Date: Thu, 29 Nov 2007 16:50:51 -0600
-----Original Message----- From: nmap-dev-bounces () insecure org [mailto:nmap-dev-bounces () insecure org] On Behalf Of Brandon Enright Sent: Thursday, November 29, 2007 4:41 PM To: Thomas Buchanan Cc: nmap-dev () insecure org; bmenrigh () ucsd edu Subject: Re: NSE loop issue with filtered ports Almost certainly. There was a file handle limitation (and thrashing) issue to which Majek and David cooked up solutions that were both applied. A minimum number of parallel NSOCK handles was set to 10 so that NSE could still get work done even when the max-parallelism was really low. Any script that tries to open up more than the max-parallelism (at least more than 10) before using them will deadlock. I suppose there could be other issues too. Can you provide your script or at least describe what triggers the issue? Brandon -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (GNU/Linux) iD8DBQFHTz/9qaGPzAsl94IRAvzpAJ4/LxB7lo8SToQH2Mj1rOrZrdzRlQCggfZq FSnowo5UK18XOJ9cjZTKrS4= =gWEw -----END PGP SIGNATURE-----
I've attached a test script that triggers the issue. It attempts a single connection to UDP port 1434 (MS SQL monitor), and reads any reply. Run against <= 10 hosts concurrently things are fine. Run against > 10 hosts, and nmap gets a little crazy. The target port doesn't really matter, as long as the port is filtered, not open or closed. I chose this one for my test script because it was convenient for me. Thomas
Attachment:
test.nse
Description: test.nse
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Current thread:
- NSE loop issue with filtered ports Thomas Buchanan (Nov 29)
- RE: NSE loop issue with filtered ports Thomas Buchanan (Nov 29)
- Re: NSE loop issue with filtered ports Brandon Enright (Nov 29)
- RE: NSE loop issue with filtered ports Thomas Buchanan (Nov 29)
- Re: NSE loop issue with filtered ports Brandon Enright (Nov 29)
- RE: NSE loop issue with filtered ports Thomas Buchanan (Nov 29)