Remotely Counting Machines Behind A NAT Box

Overtone writes "Steve Bellovin of AT&T Labs Research has published a paper showing how to remotely count the number of machines hiding behind a NAT box (in IMW 2002, the Second Internet Measurement Workshop). Your friendly DSL or cable broadband provider could implement this technique to enforce their single-machine license clause. Bellovin explains how to change the NAT software to defeat the measurement scheme, but the fix is complicated and unlikely to appear in commercial home gateways anytime soon."

Comments

What about NAT behind NAT?

[Anonymous Coward]

What about when I put a NAT machine behind a NAT machine? ;-)

FreeBSD

[PunchMonkey]

Our technique is based on the observation...that the "id" field in the IP header is generally implemented as a simple counter

Recent versions of OpenBSD and some versions of FreeBSD use a pseudo-random number generator for the IPid field.

So my FreeBSD will look like thousands of PCs? LOL, that sure would piss the cable company off.

Re:what if they are chained?

[Snork Asaurus]

if your cable company is composed of jackasses

You mean there are some that aren't?

Re:Not where I'm from

[Anonymous Coward]

Do you live in Liberty City or Vice City?

AT&T can't stand slashdotting?

[random_nick]

Not even an AT&T host can stand slashdotting?

Attention Customer:

[Snork Asaurus]

We are terminating your 28.8kbps dial-up service due to the following violation of the TOS:

Our expert system has detected that you are sharing a single connection with 4,179 computers.