[LUG.ro] NATted Hosts
Walter Castro
lugro@lugro.org.ar
Tue, 12 Aug 2003 15:20:27 -0300
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Me vino a la mente alguien que pregunto por algo asi en la lista....
A Technique for Counting NATted Hosts
Steven M. Bellovin
smb@research.att.com
AT&T Labs Research
Abstract- There have been many attempts to measure
how many hosts are on the Internet. Many of those endpoints,
however, are NAT boxes (Network Address Translators),
and actually represent several different computers.
We describe a technique for detecting NATs and counting
the number of active hosts behind them. The technique is
based on the observation that on many operating systems,
the IP header's ID field is a simple counter. By suitable
processing of trace data, packets emanating from individual
machines can be isolated, and the number of machines
determined. Our implementation, tested on aggregated local
trace data, demonstrates the feasibility (and limitations)
of the scheme.
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<P><FONT SIZE=2>Me vino a la mente alguien que pregunto por algo asi en la lista....</FONT>
</P>
<BR>
<P><FONT SIZE=2>A Technique for Counting NATted Hosts</FONT>
<BR><FONT SIZE=2>Steven M. Bellovin</FONT>
<BR><FONT SIZE=2>smb@research.att.com</FONT>
<BR><FONT SIZE=2>AT&T Labs Research</FONT>
<BR><FONT SIZE=2>Abstract- There have been many attempts to measure</FONT>
<BR><FONT SIZE=2>how many hosts are on the Internet. Many of those endpoints,</FONT>
<BR><FONT SIZE=2>however, are NAT boxes (Network Address Translators),</FONT>
<BR><FONT SIZE=2>and actually represent several different computers.</FONT>
<BR><FONT SIZE=2>We describe a technique for detecting NATs and counting</FONT>
<BR><FONT SIZE=2>the number of active hosts behind them. The technique is</FONT>
<BR><FONT SIZE=2>based on the observation that on many operating systems,</FONT>
<BR><FONT SIZE=2>the IP header's ID field is a simple counter. By suitable</FONT>
<BR><FONT SIZE=2>processing of trace data, packets emanating from individual</FONT>
<BR><FONT SIZE=2>machines can be isolated, and the number of machines</FONT>
<BR><FONT SIZE=2>determined. Our implementation, tested on aggregated local</FONT>
<BR><FONT SIZE=2>trace data, demonstrates the feasibility (and limitations)</FONT>
<BR><FONT SIZE=2>of the scheme.</FONT>
</P>
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