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<TITLE>The Answer Guy 32:
Permission to Set up a Linux Server
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<H4>"Linux Gazette...<I>making Linux just a little more fun!</I>"
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<H4 align="center">By James T. Dennis,
<a href="mailto:linux-questions-only@ssc.com">linux-questions-only@ssc.com</a>
<BR>Starshine Technical Services, <A HREF="http://www.starshine.org/">http://www.starshine.org/</A>
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<H3><img src="../gx/dennis/qbub.gif" alt="(?)"
width="50" height="28" align="left" border="0"
>Permission to Set up a Linux Server</H3>
<p><strong>From ChipX on 20 Aug 1998 </strong></p>
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<p><strong>Hi,
OK, just a quick question (sort of)...
</strong></p>
<p><strong>My friend came over one day and we were just surfing like usual
(using Win95).
</strong></p>
<p><strong>He asked if he could check his mail; I said "Sure."
So he opens up telnet and logs onto a friend's RedHat Linux 4.2 Server.
He checks mail, updates his finger, and leaves.
</strong></p>
<p><strong>I really need to know how to set up a server of my own.
</strong></p>
<p><strong>Do I need my isp's permission or some junk like that, cuz they wont be
willing to give up any of their ethernet for me and my linux box <IMG SRC="../gx/dennis/smily.gif" ALT=":)" height="24" width="20" align="middle">
</strong></p>
<blockquote><img src="../gx/dennis/bbub.gif" height="28" width="50"
alt="(!)" border="0"
>Alright, I finally figured out what you were asking.
It took a little work, though.
</blockquote>
<blockquote>First note: when you set up a Linux system it defaults
to providing many services. It is already a "server."
</blockquote>
<blockquote>What you seem to be asking is: "How do I make my server
accessible via the Internet?"
</blockquote>
<blockquote>As you surmised you would have to make arrangements with
some ISP to have some dedicated (or at least "dial on demand")
connection to the net, or to "co-locate" your hardware with
them.
</blockquote>
<blockquote>There are a number of ISP's that provide co-location services.
This is where you provide a system that they plug into
their network (and power). Generally these are moderately
expensive services (about $150 to $500 per month usually with
a limited average bandwidth utilization per month).
</blockquote>
<blockquote>Some of these plug you into their ethernet, others provide a
null modem (serial) connection over which you'd configure a
"local" (direct) PPP link. This allows them to effectively
limit the amount of bandwidth you're using. (The latest 2.1
Linux kernels have an experimental "shaper" interface that
allows one to limit bandwidth utilization on ethernet --- but
I don't know of any ISP that's using that).
</blockquote>
<blockquote>I know some businesses that co-locate an extra server for
redundancy. If their dedicated network connection gets
hit by the proverbial (and sometime very <EM>real</EM>) 'backhoe'
then their web site and mail server is still accessible to
their customers. This is relatively low cost to companies
that are used to paying for T-1, T-3, or fiber charges.
</blockquote>
<blockquote>This brings up to the second option. You can get a
dedicated connection to your home or office. These range
from 28.8 dial-up over POTS (plain old telephone service) to
OC-48 (optical connections --- even past 622Mbps). As you
might expect most of these are prohibitively expensive
for home use (not to mention potential zoning and regulatory
issues).
</blockquote>
<blockquote>For practical purposes you have the following options for
home and SOHO (small office, home office) dedicated connections:
</blockquote>
<blockquote>
<dl><dt>modem over POTS:
<dd>least expensive, might be as low as
$130 (US) per month. Slowest. As
discussed in my articles about modems
you usually won't get 56Kbps out of a
"56K" modem.
<dt>ISDN (Centrex or not):
<dd>This is usually at least $200/mo.
Centrex is a little confusing. Typically it
allows you and your ISP, if you are located in the
same telephone CO (central office), to have an
ISDN line that is essentially an extension of
your ISP's office. This typically just eliminates
the "per-minute" charges of keeping the ISDN line
up. It also limits your ISDN line so that it can
only be used with that ISP. (This also implies
a very limited selection of ISP's for each user).
<dt>DSL:
<dd>Not available in all areas. Somewhat confusing
right now since it is a fairly recent offering.
Basically DSL takes advantage of an old obscure
feature in the pricing structure and responsibilities
of US phone companies. They used to provide "dry
copper" lines (that is telephone wires with no
dial-tone or signal) to alarm companies and similar
services. Using these lines and connecting DSL
routers at each end (rather than alarm monitoring
equipment) one can get various speeds (depending
on the distances between client, CO, and ISP).
</dl>
</blockquote>
<blockquote>DSL typically costs about $300/mo where it's
available.
</blockquote>
<blockquote>If I was getting a DSL line I'd get it
from Idiom (<A HREF="http://www.idiom.com">http://www.idiom.com</A>) or some other
Covad partner (<A HREF="http://www.covad.com">http://www.covad.com</A>). I know
the owner and founder of Idiom, and one of the
principles of Covad. Those are both SF Bay
Area companies.
</blockquote>
<blockquote>
<dl><dt>56K leased line:
<dd>(I'm not a telco expert but I think this
is the same as a "fractional T1" --- that is that
is a a fraction, 1/24th of a T-1 --- which in
turn is a bundle of 24 channels for a total of
1.54Mbps). This is about as much as any sane
person would pay to put in his or her home. They
cost about $300 or more per month.
<dt>cablemodem:
<dd>These are very fast, and only available
in a <EM>very</EM> limited number of places. Also
they frequently limit your ability to provide
services (through packet filtering or by
periodically disconnecting you and assigning
new IP addresses. While they sound great for web
<dt>Frame Relay:
<dd>I've seen these in various speeds, from
56K or 64Kbps to 1.5Mbps and in various prices
ranging from $200 per month to over $1000.
<dt>Wireless:
<dd>A couple of providers in the Silicon Valley
(and San Francisco Bay Area) offer wireless
dedicated connections. One of them is
Innetix (<A HREF="http://www.innetix.com">http://www.innetix.com</A>)
</dl></blockquote>
<blockquote>Conceivably an ISP could provide "dialout" or "service
on demand" services --- that is that they could dynamically
dial your server when TCP/IP traffic is destined for your site.
(It would work almost the same way that your copy of diald
allows your system to dynamically call your ISP --- only the
underlying routes would be different).
</blockquote>
<blockquote>I've never heard of a company that actually offered this
service and I doubt that there's any advantage for them to
do so. This would probably be quite expensive for them ---
and there's probably almost no demand for it (I doubt that
one customer in a thousand would understand or care about
such a service --- and I can see any pricing niche that would
make it worthwhile).
</blockquote>
<blockquote>I only mention as a theoretical possibility.
</blockquote>
<strong><p><img src="../gx/dennis/qbub.gif" height="28" width="50"
alt="(?)" border="0">Can I do this with X?</p></strong>
<strong><p>Thanks.
<br>ChipX
</p></strong>
<blockquote><img src="../gx/dennis/bbub.gif" height="28" width="50"
alt="(!)" border="0"
>X is a communications protocol for windowing (GUI)
and keyboard/mouse events. The X Window System provides
a client/server windowing environment --- which allows
programs on your local machine, and on selected remote systems,
to act as clients on your "display server" (a display is
one or more screens, a keyboard and a mouse and/or other
pointing device).
</blockquote>
<blockquote>This is why you call the program that you run on your
Linux system an "X server" --- because it provides display
services to programs like '<tt>xterm</tt>' 'netscape' etc. The
fact that most of these programs are usually running on the
same host as the server is of no consequence to X. The
X server communicates with all of its clients via sockets.
</blockquote>
<blockquote>Those are unix domain sockets ("<tt>s</tt>" special nodes on your file
system --- usually under <tt>/tmp</tt>) for most localhost clients,
internet domain sockets (TCP/IP networking) for most others).
</blockquote>
<blockquote>So, I suppose you can do "this" with X (that is, you could
have an ISP co-located a server on the Internet, or you could
have a dedicated connection fed into your home such that you
could allow access to an X server from any client on the
Internet. This would be horrible from a security standpoint
--- but that's not something you've expressed any concern about.
</blockquote>
<blockquote>Shifting into "requirements analysis" mode we ask:
</blockquote>
<blockquote>What information, applications and resources
to you want/need to make available to whom?
</blockquote>
<blockquote>... which leads to a more fundamental requirements question:
</blockquote>
<blockquote>Who are the involved parties? (You, and each person
or class of persons to whom you would like to provide
access to the aforementioned resources).
</blockquote>
<blockquote>You can use these two lists (resources, parties/customers)
to build a table of "business relationships" (even if this
isn't really a business, the principle applies --- you relate
groups/users to the resources with verbs like "read" "write"
"execute" "append/add" etc.
</blockquote>
<blockquote>When you have a clear understanding of these things you can
evaluate and prioritize them. That is to say: you can
place values on each of these relationships. You may find
that many the items you listed are not really requirements
--- but are really preferences or constraints. That's fine,
keep them on the list.
</blockquote>
<blockquote>You could then look at your possible approaches (from the
list above, and by doing additional research into ISP
offerings in your area). All possible designs/plans which
fit your requirements without violating any of your
constraints form a "solution space." This may be an empty
set (there may be not solutions to your set of requirements
within your stated constraints). If there are multiple options
a mapping of these overlaid on your preferences may find an
optimal solution (that's why you prioritize/evaluate the
preferences --- so you can do sums and scoring).
</blockquote>
<blockquote>At that point you'd be in a position to do a cost/benefit
analysis. Undoubtedly costs/pricing formed some of your
constraints. Presumably your preference (all other things
being equal) would be to pay less. However, it is possible
that you're costs will exceed perceived or potential benefits
in such a way as to convince you to abandon the solution set
(and a whole project).
</blockquote>
<blockquote>Actually all you said about your requirements was that
you "need to know how to ...." --- hopefully you now "know";
presumably you are, or were, considering actually setting
something up and I'll have to guess beyond that.
</blockquote>
<blockquote>All I can guess about your requirements was that you
want to be able to remotely get your mail, telnet to your
machine, and update your .plan (finger info). You currently
think you want to be able to do this "over the Internet."
</blockquote>
<blockquote>I'm not sure that you've really considered alternatives
regarding this last one. If you connect a modem to your
Linux box at home you can dial in and use it from anywhere
that you can get at a modem and dial your home number. Unless
you are a real globetrotter your home is probably a local
call to you most of the time. In addition if your area
has "Ricochet" or "<a href="http://www.metricom.com/">Metricom</a>"
or <em>[Ricochet is the product sold or leased by Metricom. -- Heather]</em>
any similar service it may be that you can get a wireless "modem"
(provides a Hayes compatible AT command set and serial interface to your
computer) with optional dial out service. (This allows you
to use a "Ricochet" on your laptop, from the local coffee
house or wherever you can get a signal to dial into your
machine at home).
</blockquote>
<blockquote>Actually, oddly enough, this service has a strange idea
of locality. I subscribe to it in the SF Bay Area. This
lets me dial to any modem number in the 408, 415, 650, 510,
and nearby area codes. It also allows me to dial to 800
numbers. I can dial to these, toll free and without connect
time charges from any where that Metricom's service extends.
</blockquote>
<blockquote>Thus I've dialed into my home computer from the Burbank
Airport near L.A. and from a hotel lobby in Seattle while
I was at a USENIX conference.
</blockquote>
<blockquote>Another thing that's not evident from your question is
just what benefits you hope to get from all of this. Is
it just "coolness" --- so you can do the same thing
your friend did? If so, see if you can get an account
on this other friend's machine. Is it convenience? Do
you have any security concerns? How much is it worth do
have this much "coolness" or convenience?
</blockquote>
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<H5 align="center"><a href="http://www.linuxgazette.com/copying.html"
>Copyright &copy;</a> 1998, James T. Dennis <BR>
Published in <I>Linux Gazette</I> Issue 32 September 1998</H5>
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