Re: Private Address Spaces

From: Francois Labreque (flabreque_at_videotron.ca)
Date: 11/25/03 

Date: Tue, 25 Nov 2003 00:08:47 -0500

Program ended abnormally on 24/11/2003 10:39, Due to a catastrophic
mchiper error:
> In alt.computer.security, Msg ID: <yUkqb.12079$9M3.10754@newsread2.news.atl.earthlink.net>
> "Don Kelloway" <dkelloway@commodon.com>, wrote:
>
>
>>What you've quoted is from a post discussing the allocation of private
>>IP addresses and the problems encountered when a company decides to use
>>IP's addresses (registered to a different company) on the internal side
>>of a device which performs Network Address Translation (NAT).
>>
>>Now in regards to your comments. I'm somewhat confused. Can you better
>>explain what it is that you're trying to say and what does it have to do
>>with the above subject?
>
>
> It's so simple...
> Is my IP address..
> The one assigned to me by my ISP, so that I may connect to THEIR network
> and communicate (through THEIR router.), a PRIVATE ADDRESS SPACE.
> Yes or NO ???

No.

What is commonly referred to as "private address space" has nothing to do with
pirvacy. It is simply three ranges of IP addresses (10.x.x.x,
172.16.x.x-172.31.x.x and 192.168.x.x) that companies are recommended to use for
their internal lans to limit the wasteful usage of ip addresses. Those IP
address ranges are not routable on the internet, so if you were to use one of
them, you would not be able to contact any web site, e-mails erver, etc...

>
> IOW..
> Is it NOT merely a mumber that THEY assign to ME, so that THEY may
> direct packets from ME to OTHERS, and back to ME..
>

The ip address that you get when you connect to your ISP is indeed used so that
you may connect to other sites. Your ISP might use private addresses, but most
don't.

> Is it NOT true that they have NO NEED to disclose the ACTUAL NUMBER
> that they ASSIGNED to me, to OTHERS, to allow the communication to OCCUR..
>

If your ISP used private addresses, unless they used some sort of translation
mechanism (called NAT) at their border, the other end would not know where to
send packets back to you. The great majority of ISPs do not use NAT because it
can cause all kinds of problems with some applications that need to allow the
other end to initiate the connection (instant messengers, file-sharing
softwares, etc...) or applications that simply do not work with NAT (vpn
tunnels, etc...)

> And that when they DO, that information exposes ME to serious PROBLEMS..
>

> Further that THEY continue to INSIST that this is MY problem..

Yes. As others have pointed out, you should lock your doors at night, and don't
leave your car's windows open in the shopping center's parking lot.

>
> But, If my postman did the same thing, with the mail I put in my MAILBOX,
> (i.e. insert my REAL address on what I put in my MAILBOX), which is
> actually OWNED by the USPS, that I could have him put in JAIL.

That is a bad analogy. You send an order to a company for a parcel. You need
to tell that company where you live, so that they can send the parcel back to
you. The postman needs to be able to find your house to deliver the parcel to
you. You should also put a return address on regular mail you put in your
mailbox so that in you did not put enough stamps on it, or your intended
recipient moved, the postman can return it to you.

It is the same for Internet traffic.

> --
> Ray 

-- 
Francois Labreque | The surest sign of the existence of extra-
     flabreque     | terrestrial intelligence is that they never
         @         | bothered to come down here and visit us!
   videotron.ca    |                             - Calvin

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