[svlug] Wireless Access Point for Linux networks?

[Joey Hess]

Dagmar d'Surreal wrote:
> "obsolete" PCs.... something Linux is very good at.  You could use a
> non-pentium if you got the ISA<->PCMCIA adapter.

Indeed - I use a old 486 as my access point. I'm really keen on
recycling 486's and 386's as access points. The really big plus is these
older computers can easily be run w/o fans. I've even pulled the fan
from my power supply (being careful to well venilate the case, and
arrange it so there will be some airflow due to convection. Add the
noflushd daemon to keep the hard drive spun down (for up to 24 hours at
a strech; until the daily cron jobs run), and you have a completly
silent access point with no moving parts, for the cost of a pcmcia card
and ISA bridge.

My 486 has been up for a month in this configuration, with daytime terms
in the 90's here in VA, so I'm pretty confident it's thermally ok.

> If you'll look closely at most of the wireless PCMCIA cards you'll note
> that they have a small plastic cover (which is easily removeable with a
> fingernail) over the socket where you can plug in an antenna that's also
> available, although for not very cheaply considering it's just a
> particularly measured piece of wire with some rubber over it.

Yeah, I have a 6 foot tall "dongle" attached to my pcmcia card with a 50
foot cable. :-)

> There really isn't much difference between then, EXCEPT for this one ugly
> thing that I haven't had a chance to go throught the Linux-WVLAN page to
> see if they've gotten around it.  An AirPort base station is able to make
> WEP packets mandatory for communication with it's network.  To my
> knowledge without throwing the card into base station mode (those magic
> opcodes that were mentioned before) the cards will recieve both WEP and
> non-WEP packets and pass them both to the host computer with no way to
> distinguish between them.  This means that someone won't need WEP to
> communicate with your gateway...  so you can't readily limit access to the
> network by requiring WEP like you can with an actual AirPorter, hence my
> recommendation that you *not* allow just any old packets off the wireless
> segment to run loose on the Internet.

This does not match my experience when I was using WEP on my access
point. I was unable to ping it if I didn't have the client configured
with the key. (I just verified this.) I'm using Orinoco silver cards.

The real disadvantages are that without proprietary info about the
card's firmware, linux cannot do IP-level bridging over Ornioco cards,
and it cannot set up the cards to work in managed mode, so you're
limited to Ad-hoc networking.

-- 
see shy jo