The Linux Letter for August
Welcome back to another edition. Eagle eyed
readers will notice that this issue of the Letter is several
days late. Chalk it up to the demands of an 18 credit
engineering schedule, work and the occasional attempts to keep
the computers in the nospin.org network operations center up and
I work in research and development for a
mid-sized company in Boise, Idaho that makes things that are
designed to work with the Internet. In fact, I'll even put in a
good word for them, since they're decent enough to work with my
horrible schedule and still smile when I ask for a paycheck. The
company is Extended Systems, Inc. What, you ask, does this have
to do with this column? Plenty! Besides putting a few extra
dollars in my pocket so that I can buy computer parts and type
this article, ESI also makes a Linux-powered network appliance
that I helped develop.
The ExtendNet 4000 isn't a solo player in
the field of "thin" servers. Several other companies
produce their own versions. But before I put the cart before the
horse, let's talk about what a thin server is and how it relates
Thin servers are something fairly new. They
represent a moderately powered computer, perhaps running a
Celeron processor and 32 to 64 MB of RAM and a 4 to 10GB hard
drive. Their purpose in life is to provide a home or small
office network with a connection to the Internet that all of the
clients on that network can use. Ideally, they are transparent
to the kind of computer on the network… whether PC, Mac or
some other kind, as long as the client uses Ethernet and TCP/IP,
the server should be able to work with them.
Most of the servers on the market provide a
basic set of services like email, web hosting, proxying,
firewalls and file storage. They also allow connections to the
Internet via modem, Ethernet, ISDN or ADSL. Most are maintained
remotely, either through telnet or via a web interface.
Not all of the thin servers on the market
use Linux, and while that may not be to their detriment, the
same forces that drive prices and margins down for PC's make
business tight for thin servers. That means that any costs that
the manufacturer can shave will be reflected in the price. And
that's why Linux appears to be the operating system of choice
for this segment of the market.
But why should you purchase what is already
available for free? If you're a moderate to expert Linux user,
there's no reason! Linux already comes with a robust set of
Internet tools that, in most cases, will allow you to get on the
Internet as soon as you install the operating system on a
computer. To achieve some of the additional services, you'll
have to fiddle a bit.
Email: Every distribution that I know of
comes with Sendmail, the Internet standard email processing
program. In a default installation, Sendmail is already
Web Server: Again, I don't know of any
distribution that doesn't come with Apache configured and ready
to run. It has the largest installed base of any web servers in
File Storage: You may need to work a bit.
Linux supports NFS, the Network File System, a method of sharing
information between Linux and other UNIX boxes. Programs are
available for Windows to allow them to mount NFS volumes, but a
better choice is Samba, the Windows networking service for Linux
that allows a Linux server to act as a host in a Windows
network. Configuration ranges from extremely easy to very
torturous, depending upon your topology and system requirements,
but usually isn't too hard. The Samba HOWTO is a great help.
Proxy and Firewall Services: Sometimes you
want to maintain control of what Internet services are
accessible to your clients and how those clients should be seen
to the outside world. A proxy server like Squid accomplishes the
task. Ease of configuration tends to be the same as Samba.
Fortunately, there are HOWTOs that help.
You can even configure your thin server to
support IP Masquerading, that is, using the single IP address
from your ISP to support several computers on your network.
Again, HOWTOs are a goldmine of information.
You might get the impression that if you
purchase a ready-made thin server like the Extended Systems
Extendnet 4000, Technaut E-Server, Cobalt Qube or Rebel.com
Netwinder that most of the headaches of configuration will be
resolved for you. And for the most part, you'd be right! But if
you're a tinkerer like I am, you won't be able to resist the
lure of creating your own customized version of the manufactured
servers, something that will do exactly what you want it to do.
And you already know what it took lots of
research and development dollars to discover: Linux can do it!
Extended Systems: http://www.extendsys.com