[afnog] Some cool bits and pieces

[Brian Candler]

I've recently been playing with a few bits of cheap but useful technology. I
thought they might be of interest to some people here, especially for those
setting up Afnog workshops.

(1) "Powerline carrier", a.k.a. ethernet over mains wiring

These are little plug-in bridges with just an RJ45 socket and a power plug.
Ethernet frames are sent directly over the power lines, using frequencies in
the range 4.5-20MHz. They are genuinely "plug and play" and transparent in
operation, and very low cost. They comply to the "HomePlug" standard.

Claimed data rate is 14Mbps for the most basic devices, although I measured
a real FTP throughput closer to 3Mbps. They also claim a range of 200m.
There is a moderate degree of security, by being able to set a fixed 56-bit
DES key in each device.

Some examples:
http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=236911
http://www.broadbandcarrier.net/shop.htm#sh_wallplug_bcl_eth

May be useful for a classroom backbone, especially where walls make wireless
unreliable. However the rooms must be on the same mains phase.

(There is faster but proprietary hardware also available. A new and
recently-ratified standard, "HomePlug AV", has a raw data rate of 150Mbps.
Equipment should start becoming available in the first half of 2006)

(2) OpenWRT

A Linux distribution which runs directly on a low-cost access point. If you
have an access point with USB ports (such as the Asus WL-500G Deluxe that
I've been playing with here) then you can plug in a USB hard drive and set
it up as a standalone FTP server. You can also do lots of interesting things
with the wireless side (e.g. set it up as a client to another access point,
or as a WDS repeater), and with routing (on some hardware you can treat each
ethernet port as a separate VLAN, so have up to a 5-port ethernet router).

There are lots of packages available for doing things like RADIUS, VPNs,
even webcam support.

Certain versions of the popular Linksys WRT54G are supported, but be very
careful because the latest revision does NOT have enough RAM or ROM to run
Linux. The WRT54GL specifically *does* run Linux though.

Full details and downloads at http://www.openwrt.org/

(3) Linksys WRT54G3G

A router/access point with PCMCIA slot for 3G/GPRS data card. Set up an
instant wireless hotspot anywhere that has 3G or GPRS coverage!

http://www1.linksys.com/international/product.asp?coid=19&ipid=845

(4) OpenVPN

A simple-to-setup VPN client/server which you could use to tunnel a real IP
subnet from some other place when you only have a single IP address locally.
It's not IPSEC, but that's what makes it simple to set up :-) It can also
bridge raw ethernet frames.

http://www.openvpn.net/

Another similar non-IPSEC VPN is TINC: http://www.tinc-vpn.org/. Looks even
easier to set up, but I've not tested it.

TINC and OpenVPN are also available as OpenWRT packages, so you can run them
directly on your access point/router.
http://downloads.openwrt.org/whiterussian/packages/

(5) VMware Player

VMware have released a *free* version of their product, VMware Player. This
lets you run any virtual machine created using the full version of the
product. A number of virtual machine images are available for free download,
including an Ubuntu/Firefox bundle, Oracle and Mysql server images.

This makes it possible to run Linux under Windows, without repartitioning.
It's not as fast as a native installation, but it may be good enough as a
teaching tool without having to trash the Windows installation. In any case,
running Firefox under Linux+VMware gives you a completely safe way to browse
the Net, immunising you from virus and spyware infestation.

http://www.vmware.com/products/player/

Regards,

Brian.