OT: ADSL safe practices and setting up a home network

[Mike McCarty]

Guy Fraser wrote:
> On Fri, 2006-14-04 at 13:01 -0500, Mike McCarty wrote:
> 
>>Anne Wilson wrote:
>>
>>>On Friday 14 April 2006 15:47, Mike McCarty wrote:
>>>
>>>Your choice entirely.  Encryption does work, and I also have checked that 
>>>nothing is detectable outside my boundaries.  Then of course it can be tied 
>>>to mac addresses.  It's perfectly possible to have the facility without risk.  
>>>If you don't need it, fine.
>>
>>Any machine to which there is physical access has only
>>relative security. The fewer physical access points there
>>are the higher the relative security can be. Removing the
>>antenna almost removes one of the access points.
>>
>>I say almost because, should the firmware or hardware not
>>properly disable the wireless I/F, someone who knew I was
>>here and had a high-power transmitter and a focussed high
>>gain antenna with a sensitive receiver could still get
>>access.
>>
> 
> 
> Very true. Removing the antenna may not actually do what 
> you want, it will certainly reduce the antenna gain, but 
> does not prevent transmission or reception. What you 
> should do is install a 50 Ohm shielded terminator. You 
> will need a BNC adaptor for you antenna connector, which 

TNC. And even a 50 ohm termination (presuming that the
receiver uses 50 ohm impedance, which is almost certain,
given the frequencies involved) will not completely
isolate. And then there are IF amp. attacks, etc.

> with you to make sure you get the right one. You can 
> likely get the adaptor and terminator at an electronics 
> supply store, or from a radio system installer.

I could build my own using parts in my junk box, actually.

> We used to do a lot of wireless connections and determined 
> that even heavily shielded radios could communicate 
> effectively over a couple feet with no antennae installed 
> on either one. We also determined that using 100mW TX

Of course, this is a violation of FCC regs... :-)

[snip]

> arrays it could be possible to receive a signal covertly 
> from hundreds of feet away, but then you don't necessarily 
> need a wireless router to do that anyway.;^) If you are 

Yah, I've got a 6 foot cable running between the router and
my machine, and a 6 foot cable (coiled up, it's true) between
the router and the DSL modem, both unshieled twisted pair
(CAT5 stuff).

> interested, there are a few good articles about Tempest 
> surveillance that are enlightening. I used to work on 
> anti-tempest compliant devices for law enforcement and 
> military applications, back in the late 80's. I can only 
> imagine how much better the new tempest stuff is. :^O

http://www.fas.org/irp/program/security/tempest.htm

Mike
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