Zen and the Art of Internet | Page 9

the Internet.
On many systems, it's also the name of the program that implements the protocol. Given
proper permission, it's possible to copy a file from a computer in South Africa to one in
Los Angeles at very fast speeds (on the order of 5--10K per second). This normally
requires either a user id on both systems or a special configuration set up by the system

administrator(s).
There is a good way around this restriction---the anonymous FTP service. It essentially
will let anyone in the world have access to a certain area of disk space in a
non-threatening way. With this, people can make files publicly available with little hassle.
Some systems have dedicated entire disks or even entire computers to maintaining
extensive archives of source code and information. They include gatekeeper.dec.com
(Digital), wuarchive.wustl.edu (Washington University in Saint Louis), and
archive.cis.ohio-state.edu (The Ohio State University).
The process involves the ``foreign'' user (someone not on the system itself) creating an
FTP connection and logging into the system as the user anonymous, with an arbitrary
password:
Name (foo.site.com:you): anonymous Password: [email protected]
Custom and netiquette dictate that people respond to the Password: query with an email
address so that the sites can track the level of FTP usage, if they desire. (Addresses for
information on email addresses).
The speed of the transfer depends on the speed of the underlying link. A site that has a
9600bps SLIP connection will not get the same throughput as a system with a 56k leased
line (The Physical Connection, for more on what kinds of connections can exist in a
network). Also, the traffic of all other users on that link will affect performance. If there
are thirty people all FTPing from one site simultaneously, the load on the system (in
addition to the network connection) will degrade the overall throughput of the transfer.
FTP Etiquette
Lest we forget, the Internet is there for people to do work. People using the network and
the systems on it are doing so for a purpose, whether it be research, development,
whatever. Any heavy activity takes away from the overall performance of the network as
a whole.
The effects of an FTP connection on a site and its link can vary; the general rule of thumb
is that any extra traffic created detracts from the ability of that site's users to perform their
tasks. To help be considerate of this, it's highly recommended that FTP sessions be held
only after normal business hours for that site, preferably late at night. The possible effects
of a large transfer will be less destructive at 2 a.m. than 2 p.m. Also, remember that if it's
past dinner time in Maine, it's still early afternoon in California---think in terms of the
current time at the site that's being visited, not of local time.
Basic Commands
While there have been many extensions to the various FTP clients out there, there is a de
facto ``standard'' set that everyone expects to work. For more specific information, read
the manual for your specific FTP program. This section will only skim the bare minimum
of commands needed to operate an FTP session.

Creating the Connection
The actual command to use FTP will vary among operating systems; for the sake of
clarity, we'll use FTP here, since it's the most general form.
There are two ways to connect to a system---using its hostname or its Internet number.
Using the hostname is usually preferred. However, some sites aren't able to resolve
hostnames properly, and have no alternative. We'll assume you're able to use hostnames
for simplicity's sake. The form is
ftp somewhere.domain
Domains for help with reading and using domain names (in the example below,
somewhere.domain is ftp.uu.net).
You must first know the name of the system you want to connect to. We'll use ftp.uu.net
as an example. On your system, type:
ftp ftp.uu.net
(the actual syntax will vary depending on the type of system the connection's being made
from). It will pause momentarily then respond with the message
Connected to ftp.uu.net.
and an initial prompt will appear:
220 uunet FTP server (Version 5.100 Mon Feb 11 17:13:28 EST 1991) ready. Name
(ftp.uu.net:jm):
to which you should respond with anonymous:
220 uunet FTP server (Version 5.100 Mon Feb 11 17:13:28 EST 1991) ready. Name
(ftp.uu.net:jm): anonymous
The system will then prompt you for a password; as noted previously, a good response is
your email address:
331 Guest login ok, send ident as password. Password: [email protected] 230 Guest
login ok, access restrictions apply. ftp>
The password itself will not echo. This is to protect a user's security when he or she is
using a real account to FTP files between machines. Once you reach the ftp> prompt, you
know you're logged in and ready to go.
Notice the ftp.uu.net:joe in the Name: prompt?