From Slashdot: Comcast goes after NAT users

[Marvin Bellamy]

Can you give some details?  I don't see how it is possible to see 
machines behind an IPF/IPNAT server.

Aaron wrote:

>Of course.  Keep in mind that using IP fragmentation (with some fragment
>overlaying techniques), any Packet filtering firewall can be bypassed to
>reveal the machines behind it.  Also, you can use products like NMAP and
>Firewalk (under Linux, of course) to see if the offending machine is a
>firewall-type device and what's behind it.  Weather Comcast is that smart, I
>don't know but from what I've heard from the people on this list and some
>friends who use them, I doubt it.
>
>Aaron
>
>----- Original Message -----
>From: "Duane Attaway" <dattaway at attaway.org>
>To: "jim" <jim at weathercom.com>
>Cc: <kclug at kclug.org>
>Sent: Thursday, January 24, 2002 11:42 PM
>Subject: Re: From Slashdot: Comcast goes after NAT users
>
>
>>I have a question.  How can they technically do this?  Could this be scare
>>tactics or can they really "see" other computers behind a firewall?  Is
>>there clues in the headers that give it away?  Would they have to sniff
>>port 80 and see the odd things like different browser versions at the same
>>time (Linux Mozilla AND MSIE at the same time?)  Maybe I haven't paid much
>>attention to tcpdump, but I haven't seen any clues that any of those
>>packets from my cablemodem are going to make a few additional hops.
>>
>>On Thu, 24 Jan 2002, jim wrote:
>>
>>>Any Comcast employees want to comment on this folderol.  I only have one
>>>computer, but it's connected to the 'net via a Linksys firewall/router
>>>because Comcast won't do squat about security.  They going to come after
>>>
>me
>
>>>next?  I'm checking out DSL tomorrow.
>>>
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