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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

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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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