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GUIDE TO (mostly) HARMLESS HACKING

Vol. 2 Number 2

Linux!
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        Unix has become the primo operating system of the Internet. In fact,
Unix is the most widely used operating system in the world among computers
with more power than PCs. 
True, Windows NT is coming up fast as a common Internet operating system,
and is sooo wonderfully buggy that it looks like it could  become the number
one favorite to crack into. But today Unix in all its wonderful flavors
still is the operating system to know  in order to be a truly elite hacker.

        So far we have assumed that you have been hacking using a shell
account that you get through your Internet Service Provider (ISP). A shell
account allows you to give Unix commands on one of your ISP's computers. But
you don't need to depend on your ISP for a machine that lets you play with
Unix. You can run Unix on your own computer and with a SLIP or PPP
connection be directly connected to the Internet. 

***********************
Newbie note: Serial Line Internet Protocol (SLIP) and Point-to-Point
Protocol (PPP) connections give you a temporary Internet Protocol (IP)
address that allows you to be hooked directly to the Internet. You have to
use either SLIP or PPP connections to get to use a Web browser that gives
you pictures instead on text only. So if you can see pictures on the Web,
you already have one of these available to you.

        The advantage of using one of these direct connections for your
hacking activities is that you will not leave behind a shell log file for
your ISP's sysadmin to pore over. Even if you are not breaking the law, a
shell log file that shows you doing lots of hackerish stuph can be enough
for some sysadmins to summarily close your account.
********************

        What is the best kind of computer to run Unix on? Unless you are a
wealthy hacker who thinks nothing of buying a Sun SPARC workstation, you'll
probably do best with some sort of PC. There are almost countless variants
of Unix that run on PCs. Most of them are free for download, or
inexpensively available on CD-ROMs.

        The three primary variations of Unix that run on PCs are Sun's
Solaris, FreeBSD and Linux. Solaris costs around $700. Enough said. FreeBSD
is really, really good but doesn't offer a lot of support. Linux, however,
has the advantage of being available in many variants (so you can have fun
mixing and matching programs from different Linux offerings). Most
importantly, Linux is supported by many news groups, mail lists and Web
sites. If you have hacker friends in your area, most of them probably use
Linux and can help you out.

*********************
Historical note: Linux was created in 1991 by a group led by Linus Torvalds
of the University of Helsinki.  Linux is copyrighted under the GNU General
Public License. Under this agreement, Linux may be redistributed to anyone
along with the source code. Anyone can sell any variant of Linux and modify
it and repackage it. But even if someone modifies the source code he or she
may not claim copyright for anything created from Linux. Anyone who sells a
modified version of Linux must provide source code to the buyers and allow
them to reuse it in their commercial products without charging licensing
fees. This arrangement is known as a "copyleft."

        Under this arrangement the original creators of Linux receive no
licensing or shareware fees. Linus Torvalds and the many others who have
contributed to Linux have done so from the joy of programming and a sense of
community with all of us who will hopefully use Linux in the spirit of good
guy hacking. Viva la Linux! Viva Torvalds!
**********************

        Linux consists of the operating system itself (called the "kernel")
plus a set of  associated programs. 

        The kernel, like all types of Unix, is a multitasking, multi-user
operating system. Although it uses a different file structure, and hence is
not directly compatible with DOS and Windows, it is so flexible that many
DOS and Windows programs can be run while in Linux. So a power user will
probably want to boot up in Linux and then be able to run DOS and Windows
programs from Linux.

        Associated programs that come with most Linux distributions may include:
* a shell program (Bourne Again Shell -- BASH -- is most common);
* compilers for programming languages such as Fortran-77 (my favorite!), C,
C++, Pascal, LISP, Modula-2, Ada, Basic (the best language for a beginner),
and Smalltalk.;
* X (sometimes called X-windows), a graphical user interface
* utility programs such as the email reader Pine (my favorite) and Elm

Top ten reasons to install Linux on your PC:
1.      When Linux is outlawed, only outlaws will own Linux.
2.      When installing Linux, it is so much fun to run fdisk without backing up
first.
3.      The flames you get from asking questions on Linux newsgroups are of a
higher quality than the flames you get for posting to alt.sex.bestiality.
4.      No matter what flavor of Linux you install, you'll find out tomorrow
there was a far more 3l1te version you should have gotten instead.
5.      People who use Free BSD or Solaris will not make fun of you. They will
offer their sympathy instead.
6.      At the next Def Con you'll be able to say stuph like "so then I su-ed to
his account and grepped all his files for 'kissyface'."  Oops, grepping
other people's files is a no-no, forget I ever suggested it.
7.      Port surf in privacy.
8.      One word: scripts.
9.      Installing Linux on your office PC is like being a postal worker and
bringing an Uzi to work. 
10.     But - -  if you install Linux on your office computer, you boss won't
have a clue what that means.

        What types of Linux work best? It depends on what you really want.
Redhat Linux is famed for being the easiest to install. The Walnut Creek
Linux 3.0 CD-ROM set is also really easy to install -- for Linux, that is!
My approach has been to get lots of Linux versions and mix and match the
best from each distribution.

        I like the Walnut Creek version best because with my brand X
hardware, its autodetection feature was a life-saver.

        INSTALLING LINUX is not for the faint of heart! Several tips for
surviving installation are:

1) Although you in theory can run Linux on a 286 with 4 MB RAM and two
floppy drives, it is *much* easier with a 486 or above with 8 MB RAM, a
CD-ROM, and at least 200 MB free hard disk space.

2) Know as much as possible about what type of mother board, modem, hard
disk, CD-ROM, and video card you have. If you have any documentation for
these, have them on hand to reference during installation.

3) It works better to use hardware that is name-brand and somewhat out of
date on your computer. Because Linux is freeware, it doesn't offer device
drivers for all the latest hardware. And if your hardware is like mine --
lots of Brand X and El Cheapo stuph, you can take  a long time experimenting
with what drivers will work.

4) Before beginning installation, back up your hard disk(s)! In theory you
can install Linux without harming your DOS/Windows files. But we are all
human, especially if following the advice of 3). 

5) Get more than one Linux distribution. The first time I successfully
installed Linux, I finally hit on something that worked by using the boot
disk from one distribution with the CD-ROM for another. In any case, each
Linux distribution had different utility programs, operating system
emulators, compilers and more. Add them all to your system and you will be
set up to become beyond elite.

6) Buy a book or two or three on Linux. I didn't like any of them! But they
are better than nothing. Most books on Linux come with one or two CD-ROMs
that can be used to install Linux. But I found that what was in the books
did not exactly coincide with what was on the CD-ROMs.

7) I recommend drinking while installing. It may not make debugging go any
faster, but at least you won't care how hard it is.

        Now I can almost guarantee that even following all these 6 pieces of
advice, you will still have problems installing Linux. Oh, do I have 7
advisories up there? Forget number 7. But be of good cheer, since everyone
else also suffers mightily when installing and using Linux, the Internet has
an incredible wealth of resources for the Linux-challenged.

        If you are allergic to getting flamed, you can start out with Linux
support Web sites.

        The best I have found is http://sunsite.unc.edu:/pub/Linux/. It
includes  the Linux Frequently Asked  Questions list (FAQ), available from
sunsite.unc.edu:/pub/Linux/docs/FAQ.

        In the directory /pub/Linux/docs on sunsite.unc.edu you'll find a
number of other documents about Linux, including the Linux INFO-SHEET and
META-FAQ,

        The Linux HOWTO archive is on sunsite.unc.edu:/pub/Linux/docs/HOWTO.
The  directory /pub/Linux/docs/LDP on sunsite.unc.edu contains the current
set of LDP manuals.

        You can get ``Linux  Installation and Getting Started'' from
sunsite.unc.edu in  /pub/Linux/docs/LDP/install-guide.  The README file
there describes  how you can order a printed copy of the book of the same
name (about 180 pages).

        Now if you don't mind getting flamed, you may want to post questions
to the amazing number of Usenet news groups that cover Linux. These include:

comp.os.linux.advocacy                          Benefits of Linux compared
comp.os.linux.development.system                Linux kernels, device drivers
comp.os.linux.x                                 Linux X Window System servers
comp.os.linux.development.apps                  Writing Linux applications
comp.os.linux.hardware                          Hardware compatibility
comp.os.linux.setup                             Linux installation
comp.os.linux.networking                        Networking and communications
comp.os.linux.answers                           FAQs, How-To's, READMEs, etc.
linux.redhat.misc
alt.os.linux                                    Use comp.os.linux.* instead
alt.uu.comp.os.linux.questions                  Usenet University helps you
comp.os.linux.announce                          Announcements important to Linux
comp.os.linux.misc                              Linux-specific topics

        Tobin Fricke has also pointed out that "free copies of Linux CD-ROMs
are available the Linux Support & CD Givaway web site at
http://emile.math.ucsb.edu:8000/giveaway.html. This is a project where
people donate Linux CD's that they don't need any more. The project was
seeded by Linux Systems Labs, who donated 800 Linux CDs initially!  Please
remember to donate your Linux CD's when you are done with them.  If you live
near a computer swap meet, Fry's, Microcenter, or other such place, look for
Linux CD's there.  They are usually under $20, which is an excellent
investment.  I personally like the Linux Developer's Resource by Infomagic,
which is now up to a seven CD set, I believe, which includes all major Linux
distributions (Slackware, Redhat, Debian, Linux for DEC Alpha to name a few)
plus mirrors of tsx11.mit.edu and sunsite.unc.edu/pub/linux plus much more.
You should also visit the WONDERFUL linux page at
http://sunsite.unc.edu/linux, which has tons of information, as well as the
http://www.linux.org/.  You might also want to check out
http://www.redhat.com/ and http://www.caldera.com/ for more information on
commercial versions of linux (which are still freely available under GNU)."

        How about Linux security? Yes, Linux, like every operating system,
is imperfect. Eminently hackable, if you really want to know. So if you want
to find out how to secure your Linux system, or if you should come across
one of the many ISPs that use Linux and want to go exploring (oops, forget I
wrote that), here's where you can go for info:

ftp://info.cert.org/pub/cert_advisories/CA-94:01.network.monitoring.attacks
ftp://info.cert.org/pub/tech_tips/root_compromise
http://bach.cis.temple.edu/linux/linux-security/

        Last but not least, if you want to ask Linux questions on the Happy
Hacker list, you're welcome. We may be the blind leading the blind, but what
the heck!

_________________________________________________________
Want to see back issues of Guide to (mostly) Harmless Hacking? See
http://www.feist.com/~tqdb/evis-unv.html. Want to subscribe to this list?
Email majordomo@edm.net with the message "subscribe happyhacker." Want to
share some kewl stuph with the Happy Hacker list? Send your messages to
hh@edm.net.  To send me confidential email (please, no discussions of
illegal activities) use cmeinel@techbroker.com. Please direct flames to
dev/null@techbroker.com. Happy hacking! 

Copyright 1996 Carolyn P. Meinel. You may forward the GUIDE TO (mostly)
HARMLESS HACKING as long as you leave this notice at the end..
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M/B Research -- The Technology Brokers