     ARPANET HOPPING: AMERICA'S NEWEST PASTIME
            [2600 -- June 1984]

     ARPANET (Advanced Research Projects Agency Network) has been
around since the 1960's. Its intentions were to link many computers
together in order to share resources. The various research projects
on ARPANET involve both major universities and the United States
military (the two are closer than either would care to admit).

     Up until 1983, ARPANET was one big happy family of military and
university computers. Then, in view of War Games, etc., it was
decided that perhaps the military would be better off on their own
separate network. And so, MILNET was established.

     This proved to be very convenient for hackers, since they now
knew where all of the military computers were--all it took was access
to MILNET in order to play with them.

     Since ARPANET can communicate with MILNET and vice versa, all
kinds of interesting possibilities exist. Elaborate routing makes it
easier for a hacker to cover his trail, in much the same way that a
phreak routes calls through three diferrent long distance companies
to protect his/her identity.

     Where can dialups to ARPANET be found? All over the place.  For
one thing, many numbers are in circulation among hackers.  For
another, they're not considered all that much of a secret, since the
numbers by themselves don't allow you to logon.

     If you know of a major university computer, there's a chance
that it's already hooked into the ARPANET. If this is the case, HELP
files will be readily available on that system to explain how to
access the network.

     The network itself is an entire world waiting to be explored.
Ironically, many sensitive computers are 'not accessible by phone
lines' are accessible by ARPANET! There are a lot of lessons that
still must be learned, it seems.

          So Simple A Child Could Di It!

     Moving around ARPANET is very easy as almost any hacker that has
used it will attest to. It was designed upon the principle that
people on one system should have easy access to other systems. 'Easy'
is the keyword here. If a direct ARPANET dialup is being used, there
shouldn't be any problem. If a MILNET dialup is being used, you will
need a TACID, which is a private authorization code.

     The word ARPANET is used to denote all networks. There are many
networks, but all can be accessed as one through 'gateways', which
are basically windows into other networks.

          How It Works

     There are two basic commands that can be used on ARPANET: '@o'
and '@c'. '@o' opens a connection with a host. For example, @o
26.0.0.1 will connect you with a host hooked to ARPANET -- indicated
by the 26. Finding addresses is really the only hard part.At one
time, a few systems had a HOST command that would give you a complete
listing of hosts, and their addresses. In fact, this command is still
on many systems but what was unique here was the fact that you could
run the program without logging in!! Apparently, they got wise to
hackers, and fixed HOST so that it only works from logged in
accounts.

     After typing '@o', the network will respond with 'Open' or, if
the attempt was less than successful, a self-explanatory error
message such as 'Bad' or 'Destination host dead'. When you get the
'Open' message, that means you are now connected to the host computer
and you can do whatever you want, like login, read help files, etc.
Communication with the network is not cut off, however. The network
is always there, waiting to be spoken to.  Commands to the network
must begin with '@'. For example, type '@c' when you want to close
the connection with whatever computer you have hooked into. This will
probably take a moment or two, since the network has to close up a
few things before it can transfer control back to you. Incidentally,
if you need to send a command to the remote host that contains '@' in
it, simply type an extra '@' next to the first one and ARPANET will
ignore it.

          Some Safety Tips and Interesting Programs

     If you can dialup to a host that is connected to ARPANET, and
you have an account on it, this is ideal. There is a good chance that
the host will support a terminal simulation program, that when
supplied the host name that you wish to communicate with, will
connect you to it through ARPANET. It will then seem as if you're on
a terminal connected to that remote host. To close the connection,
you have to read the documentation on the host that you dialed up to,
since it changes from system to system. Naturally, using a local
dialup to access a host instead of going through a MILNET or ARPANET
dialup is much 'safer', since you are not accessing ARPANET directly.

     Another feature of ARPANET is the FINGER command available on
most TOPS-20 systems, and many other types as well. The FINGER
command will provide you with a listing of people currently logged
into the system, with some information on them, such as their full
name, where their terminal is located, and what their account is
known as. You will also show up on a finger, and it will show whether
you're on a remote host or not.  FINGER followed by a valid account
on that system will give you some very detailed info on that person.
One other very nice feature of FINGER is that you can supply a remote
host name, and get a listing of people on another host, without
connecting to it!! For example, FINGER @SRI-NIC will give you a
listing of people logged onto the Network Info Center. Another
program that gives details on users (though not as much) is SYSTAT.
Both can, in many cases, be run without logging in, and many HELP
files are also accessible without logging in. Certain HELP files give
information on login formats or list dialup numbers.

     If you have an account on a system, chances are quite good that
that system will support FTP, which is short for File Transfer
Program. This allows you to take files from one system, and copy them
to the system you are on. The one problem here is that you will need
a valid account to use on the system you wish to take the files from.
Most, if not all, TOPS-20 systems support file transfers, and
consequentaly have an account set aside for that purpose. The account
is called 'ANONYMOUS' and it works with any password. Some other
hosts use the account 'ANONYMOUS' as well, but they are by no means
consistent. The way file transfers work is through a FTP on the
system that you're presently on. This program communicates through
ARPANET with the host you want to take the files from. On the remote
host, there will be a program running that will take requests from
other hosts, and transmit files through the network to them. You can
do more than take files, though. You can transmit files from the host
you are on to the remote host, or get a directory of an account on
the remote host. It's very handy to get a file from SRI-NIC which
contains all network base addresses, addresses of gateways (ways of
getting from one network to another), and addresses of all hosts on
all networks.

     And of course, there's the ARPANET mail system, which allows you
to communicate with any ARPANET user. It works in a similar fashion
to FTP and FINGER as far as roaming the network to find a matching
username or host ID. It is still said that there is a very active
hacker community living in ARPANET mailboxes and it hardly seems
suprising when considering how fast and efficiently this mail system
works.

          The Future

     Since ARPANET was designed to be, and is still being used by
people who are not familiar with computers, it will always be easy to
use ARPANET, and 'hop' about it. It's very unlikely that they will
change it in any way, since it is, for the most part, pretty good at
keeping hackers away from the things they're not supposed to be
looking at.

     Maybe...

     [Courtesy of BIOC Agent 003]
