Internet DRAFT - draft-ietf-uswg-primer
draft-ietf-uswg-primer
``INTERNET-DRAFT'' Expires: 5 December 1994 ``INTERNET-DRAFT''
User Services Working Group G.C. Kessler
``INTERNET-DRAFT'': S.D. Shepard
FYI: 2x Hill Associates, Inc.
Category: Informational (DRAFT) xxxx 1994
A Primer On Internet and TCP/IP Tools (DRAFT)
<draft-ietf-uswg-primer-00.txt>
Status of this Memo
This document is an Internet-Draft. Internet-Drafts are
working documents of the Internet Engineering Task Force
(IETF), its areas, and its working groups. Note that other
groups may also distribute working documents as
Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six
months. Internet-Drafts may be updated, replaced, or obsoleted
by other documents at any time. It is not appropriate to use
Internet-Drafts as reference material or to cite them other
than as a ``working draft'' or ``work in progress.''
To learn the current status of any Internet-Draft, please check
the 1id-abstracts.txt listing contained in the Internet-Drafts
Shadow Directories on ds.internic.net, nic.nordu.net,
ftp.isi.edu, or munnari.oz.au.
Table of Contents
1. Introduction .................................................. 1
2. A Starter's Guide to Some of the Utilities and Applications ...
2.1. NSLOOKUP ....................................................
2.2. PING ........................................................
2.3. TRACEROUTE ..................................................
2.4. FINGER ......................................................
2.5. FTP .........................................................
2.6. TELNET ......................................................
2.7. User Database Lookup Tools ..................................
2.7.1. WHOIS/NICNAME .............................................
2.7.2. KNOWBOT ...................................................
2.7.3. NETFIND ...................................................
2.8. Information Servers .........................................
2.8.1. ARCHIE ....................................................
2.8.2. GOPHER ....................................................
2.8.3. Other Information Servers .................................
2.9. Electronic Mail and SMTP ....................................
2.10. Getting Even More Information On-line ......................
2.10.1. Distribution Lists and Mailing Lists .....................
2.10.1.1. Internet Discussion Lists ..............................
2.10.1.2. USENET .................................................
2.10.1.3 BITNET/EARN ............................................
2.10.2. Request for Comments (RFCs) ..............................
2.10.3. Internet Standards .......................................
2.10.4. Getting FYIs .............................................
2.10.5. Perusing the Internet ....................................
2.10.6. Getting Connected ........................................
3. Acronyms and Abbreviations ....................................
4. Security Considerations .......................................
5. Acknowledgements ..............................................
6. References ....................................................
7. Authors' Address ..............................................
1. Introduction
An ever-increasing number of people are using the Internet and, many
for the first time, are using the tools and utilities that at one
time were only available on a limited number of computer systems (and
only for really intense users!). One sign of this growth in use has
been the significant number of TCP/IP and Internet books, articles,
courses, and even TV shows that have become available in the last
year.
Most of the popular literature, however, has been oriented towards
the system administrator or network manager at a site, and even the
"introductory topics" intimidate the first-time users. Many sites,
in fact, could use a basic guide that teaches their users how to
access the common utilities found in today's TCP/IP packages for
mainframes and personal computers alike.
This ``INTERNET-DRAFT'' is a brief guide to some of the TCP/IP and
Internet tools and utilities that allow users to access the wide
variety of information on the network, from finding out if a
particular host is up and running to a multimedia thesis on foreign
policy. This is meant as a brief guide for the end user and will
refer to other sources for more detailed information. It can act
as a tutorial or laboratory manual for new users first using the
Internet and TCP/IP tools and utilities.
This ``INTERNET-DRAFT'' assumes that users will be using TCP/IP,
but does not provide any detail nor motivation about the Internet
Protocol Suite. More information on TCP/IP and related issues may
be found in [tt], [za], and [zb].
2. A Starter's Guide to Some of the Utilities and Applications
This section provides detailed descriptions and examples of several
TCP/IP utilities and applications. These sections include actual
sessions using these utilities (with some extraneous information
removed). Most of the sample dialogues shown below were made using
the Multinet TCP/IP software for VAX/VMS systems. While these
examples can be used as a guide to using and learning about the
capabilities of these tools, the reader should understand that not
all applications may be found at all TCP/IP hosts nor in all
commercial software packages. Furthermore, the user interface for
different packages will be different and the actual command line may
appear differently than shown here; this will be particularly true
for graphic user interfaces such as Windows, OS/2, or the Mac. The
Internet has many exciting things to offer but standardized
interfaces to the protocols is not yet one of them!
In the sections below, any option or parameter shown in square
brackets ([]) is optional, and the vertical-bar (|) means "or".
2.1. NSLOOKUP
NSLOOKUP is the name server lookup program that comes with many
TCP/IP systems. With NSLOOKUP, a user can determine a host system's
IP address from its name or its name from the IP address. The form
of the command to make a single query is:
NSLOOKUP IP_address | host_name
Alternatively, the program may be started by typing "NSLOOKUP"
without any parameters. At the prompt, the user can enter either an
IP address or host name, and the program will respond with the name
and address of the default name sever, the actual name server used to
resolve each request, and the IP address and host name that was
queried. "Exit" is used to quit the NSLOOKUP application.
Three queries are shown in the example below:
1 Requests the address of the host named "emily.uvm.edu", a system at
the University of Vermont (UVM). As it turns out, this is not the
true name of the host, but a shortened version of the name that is
accepted as an alias by the network. The full name of the host and
the IP address are listed by NSLOOKUP.
2 Requests the address of host "emily.emba.uvm.edu". This is, of
course, the same address as in the first query, but note that
NSLOOKUP provides a "non-authoritative" answer. Since NSLOOKUP
just queried this same address, the information is still in its
cache memory; therefore, rather than send additional messages to
the name server, we get an answer that it remembers from before.
Since we didn't look up the information again, it is not guaranteed
to still be accurate (because the information might have changed
within the last few milliseconds!).
3 Requests the name of the host with the given IP address. The
result points to the Internet gateway to Australia, munnari.oz.au.
=====================================================================
SMCVAX$ NSLOOKUP
Default Server: LOCALHOST
Address: 127.0.0.1
> EMILY.UVM.EDU
Server: LOCALHOST
Address: 127.0.0.1
Name: emily.emba.uvm.edu
Address: 132.198.1.7
Aliases: emily.uvm.edu
> EMILY.EMBA.UVM.EDU
Server: LOCALHOST
Address: 127.0.0.1
Non-authoritative answer:
Name: emily.emba.uvm.edu
Address: 132.198.1.7
> 128.250.1.21
Server: LOCALHOST
Address: 127.0.0.1
Name: munnari.OZ.AU
Address: 128.250.1.21
> EXIT
SMCVAX$
=====================================================================
2.2. PING
Ping is probably the most widely available tool available on TCP/IP
systems and uses the Internet Control Message Protocol (ICMP) Echo
messages. The Ping command has the following general format:
ping [-s] host_name [size] [quantity]
In the first test below, we ping the host "thumper.bellcore.com" to
determine whether it is up and running. This simple use of the
command contains no optional parameters.
In the second test, we use the "-s" parameter to tell our system to
send an ICMP Echo message every second. The optional "size"
parameter specifies that each message should be 64 bytes in length
(which is the default size); the optional "quantity" parameter
indicates that this test will only send 12 messages (the default is
to run the test continuously until interrupted). The results of the
second test displays the round-trip delay of each Echo message that
is returned to the sending host. At the end of the test, summary
statistics are displayed.
=====================================================================
SMCVAX$ PING THUMPER.BELLCORE.COM
thumper.bellcore.com is alive
SMCVAX$ PING -S THUMPER.BELLCORE.COM 64 12
PING THUMPER.BELLCORE.COM (128.96.41.1): 56 data bytes
64 bytes from 128.96.41.1: icmp_seq=0 time=150 ms
64 bytes from 128.96.41.1: icmp_seq=1 time=110 ms
64 bytes from 128.96.41.1: icmp_seq=2 time=130 ms
64 bytes from 128.96.41.1: icmp_seq=3 time=130 ms
64 bytes from 128.96.41.1: icmp_seq=4 time=320 ms
64 bytes from 128.96.41.1: icmp_seq=5 time=110 ms
64 bytes from 128.96.41.1: icmp_seq=6 time=440 ms
64 bytes from 128.96.41.1: icmp_seq=7 time=90 ms
64 bytes from 128.96.41.1: icmp_seq=9 time=100 ms
64 bytes from 128.96.41.1: icmp_seq=10 time=110 ms
----THUMPER.BELLCORE.COM PING Statistics----
12 packets transmitted, 10 packets received, 16% packet loss
round-trip (ms) min/avg/max = 90/169/440
SMCVAX$
=====================================================================
2.3. TRACEROUTE
Traceroute is another common TCP/IP tool, this one allowing users to
learn about the route that packets take from your system to a remote
system; it provides some interesting information that can also be
used as a powerful debugging aid. Traceroute is sometimes packaged
as an option of the Ping command.
Traceroute works by sending a sequence of User Datagram Protocol
(UDP) datagrams to an invalid port at the desired remote system.
Using the default settings, three datagrams are sent, each with a
Time-To-Live (TTL) field value set to one. The TTL value of 1 causes
the datagram to "timeout" as soon as it hits the first router in the
path; this router will then respond with an ICMP error message
indicating that the datagram has expired. Another three UDP messages
are now sent, each with the TTL value set to 2, which causes the
second router to return ICMP replies. This process continues until
we actually reach the other destination. Since these datagrams are
trying to access an invalid port at the destination host, however,
ICMP error messages are returned from the destination indicating an
unavailable port; this event signals the Traceroute program that it
is done! The Traceroute program displays the round-trip delay
associated with each of the attempts. Note that the delay associated
with the first message is usually longer than the two subsequent
messages, which may be due to the use of the Address Resolution
Protocol (ARP) to determine the route for the initial packet.
The Traceroute command has the following general format (where "#"
represents a positive integer value associated with the qualifier):
traceroute [-m #] [-q #] [-w #] [-p #]
where -m is the maximum allowable TTL value, measured in the
number of hops allowed before the program terminates
(default = 30)
-q is the number of UDP packets that will be sent with each
time-to-live setting (default = 3)
-w is the amount of time, in seconds, to wait for an answer
from a particular router before giving up (default = 5)
-p is the invalid port address at the remote host (default =
33434)
As an interesting aside, Traceroute did not begin life as a general-
purpose utility, but as a quick-and-dirty debugging aid used to find
a routing problem. The code (complete with comments!) is available
by anonymous FTP in the file "traceroute.tar.Z" from the host
"ftp.ee.lbl.gov".
The Traceroute example below shows the route between a VAX at St.
Michael's College in Vermont (smcvax.smcvt.edu) and a system at
Bellcore in New Jersey (thumper.bellcore.com). The output has some
interesting points:
1 NEARnet is the New England Academic and Research Network, a
regional network in the northeastern U.S. The route runs from St.
Mike's NEARnet gateway (smc-gw) to the University of Vermont (uvm),
etc. Note that some intermediate systems (see lines 4 and 16) do
not have names associated with them.
2 From NEARnet (lines 1-6), the datagrams traveled on the NSFNET's T3
backbone (lines 7-11); note that the NSFNET backbone is identified
as ans.net since it is operated by Advanced Networks and Services,
Inc. (ANS). The packet traveled within ANS' networks on their core
nodal switching subsystems (designated "cnss") until it was ready
to jump off the backbone; line 11 indicates an ANS exterior nodal
switching subsystem ("enss"). After the NSFNET backbone, the
datagrams were carried on the JvNCnet (lines 12-16), a regional
network in New Jersey (note the use of SMDS!). Finally, the
datagrams are placed on Bellcore's internal network (lines 17 and
18) for final delivery.
3 Note that not all of the datagrams took the same route. In
particular, only two of the datagrams went through the ANS gateway
referred to at line 10. Note also line 17; here, the first two
datagrams went through one router at Bellcore, while the third
datagram went through a companion router.
=====================================================================
SMCVAX$ TRACEROUTE THUMPER.BELLCORE.COM
traceroute to THUMPER.BELLCORE.COM (128.96.41.1), 30 hops max, 38
byte packets
1 smc-gw.near.net (192.80.64.5) 50 ms 20 ms 10 ms
2 uvm-gw.near.net (131.192.152.1) 160 ms 50 ms 30 ms
3 harvard-gw.near.net (131.192.65.1) 470 ms 60 ms 60 ms
4 131.192.32.3 (131.192.32.3) 50 ms 50 ms 40 ms
5 mit2-gw.near.net (131.192.7.1) 50 ms 40 ms 40 ms
6 enss.near.net (192.54.222.6) 60 ms 90 ms 40 ms
7 t3-2.Hartford-cnss49.t3.ans.net (140.222.49.3) 70 ms 100 ms 60 ms
8 t3-3.Hartford-cnss48.t3.ans.net (140.222.48.4) 70 ms 40 ms 40 ms
9 t3-2.New-York-cnss32.t3.ans.net (140.222.32.3) 50 ms 60 ms 70 ms
10 * t3-0.New-York-cnss33.t3.ans.net (140.222.33.1) 340 ms 110 ms
11 t3-0.enss137.t3.ans.net (140.222.137.1) 90 ms 420 ms 190 ms
12 zaphod-gateway.jvnc.net (192.12.211.65) 70 ms 50 ms 70 ms
13 airport1-gateway.jvnc.net (130.94.6.250) 390 ms 110 ms 60 ms
14 airport4-gateway.jvnc.net (130.94.7.4) 70 ms 50 ms 60 ms
15 coreSMDS-gateway.jvnc.net (130.94.7.106) 80 ms 130 ms 100 ms
16 128.96.58.2 (128.96.58.2) 80 ms 70 ms 100 ms
17 lab214b-cisco.cc.bellcore.com (128.96.34.40) 120 ms 120 ms
lab214-cisco.cc.bellcore.com (128.96.34.101) 130 ms
18 thumper.bellcore.com (128.96.41.1) 130 ms 430 ms 80 ms
SMCVAX$
=====================================================================
2.4. FINGER
The Finger program may be used to find out who is logged in on
another system or to find out detailed information about a specific
user. This command has also introduced a brand new verb; "fingering"
someone on the Internet is not necessarily a rude thing to do! The
Finger User Information Protocol is described in [uu]. The most
general format of the Finger command is:
FINGER [username]@host_name
The first example below shows the result of fingering an individual
user at a remote system. The first line of the response shows the
username, the user's real name, their process identifier,
application, and terminal port number. The remaining information is
supplied, at the option of the user, in a "plan" file that they
supply; this file is often named PLAN.TXT and resides in a user's
root directory (or somewhere in an appropriate search path).
The second example shows the result of fingering a remote system.
This lists all of the processes currently running at the fingered
system or other information, depending upon how the remote system's
administrator set up the system to respond to the Finger command.
=====================================================================
hill> FINGER KUMQUAT@SMCVAX.SMCVT.EDU
[smcvax.smcvt.edu]
KUMQUAT Gary Kessler 20A02991 TELNET TXA3
Plan:
-------------------------------------------------------------------
Gary C. Kessler
Adjunct Faculty Member, Graduate College
Senior Member of Technical Staff
Hill Associates +1 802-655-8633 or 655-0940 (office)
17 Roosevelt Highway +1 802-655-7974 (fax)
Colchester, VT 05446 +1 802-879-5242 (home)
INTERNET: kumquat@smcvax.smcvt.edu
-------------------------------------------------------------------
hill> FINGER @SMCVAX.SMCVT.EDU
[smcvax.smcvt.edu]
Tuesday, March 15, 1994 2:52PM-EDT Up 3 19:55:51
10+0 Jobs on SMCVAX Load ave 2.12 1.54 1.53
User Personal Name Subsys
DAMERON George Dameron *DCL*
GOODWIN Dave Goodwin RTPAD
JAT John Trono EDT
KUMQUAT Gary Kessler TELNET
LEAHEY Margy Leahey MAIL
NELSON Mark Nelson *DCL*
SUOZZI Patricia Suozzi MAIL
SYSTEM System Manager *DCL*
S_BRIDGE Stephen Bridge *DCL*
X_DONG Xiaofan Dong TALK
hill>
=====================================================================
2.5. FTP
The File Transfer Protocol (FTP) [vb] is one of the most useful and
powerful TCP/IP applications for the general user. FTP allows users
to upload and download files between local and remote hosts.
Anonymous FTP, in particular, is commonly available at file archive
sites to allow users to access files without having to pre-establish
an account at the remote host.
FTP can be initiated in several ways. In the example shown here, an
FTP control connection is initiated to a host by using the command
"FTP host_name". Optionally, the host's IP address (in dotted
decimal form) could be used instead of the host's name. A third
alternative would have been to start the FTP application by using
only the command "FTP"; the connection to the host could then be
initiated by typing the host_name, "OPEN host_name", or "OPEN
IP_address".
The remote host will now ask for a username and password. If a
username and password are supplied that identify a legitimate user of
this host, the user will have access to any files and directories to
which this username has privilege. For anonymous FTP access, the
username "anonymous" is used and the password (not shown in actual
use) is "guest" (most systems ask that anonymous FTP users supply
their Internet address as the password).
The first command issued in the example below is "help ?", used to
obtain a list of available FTP commands and help topics. Although
not always shown, nearly all TCP/IP applications have a help command.
An example of the help for FTP's "type" command is shown in the
sample dialogue.
The "dir" command provides a directory listing of the files in the
current directory; the UNIX-like "ls" command may also usually be
used. Note that a second FTP data transfer connection is established
for the transfer of the directory information to the local host. The
output from the "dir" command will show a file listing that is
consistent with the native operating system of the remote host.
Although the TCP/IP suite is often associated with UNIX, it can (and
does) run with nearly all common operating systems. The directory
information shown in the sample dialogue happens to be in UNIX format
and includes the following information:
o File attributes. The first character identifies this as a
directory (d), link (l), or individual file (-). The next nine
characters list the access permissions for three groups, namely,
the owner, the owner's group, and all other users. Three access
privileges may be assigned to each file for each of these groups:
read (r), write (w), execute (x), and/or search (s).
o File owner and owner's group.
o File size, in bytes.
o Date of last modification. If the date is followed by a timestamp,
then the date is from the current year.
o File name.
After the directory information has been transferred, FTP closes the
data transfer connection.
The command "cd" is used to change to another directory, in this case
the "Gov" directory (note that file and directory names may be case-
sensitive). As in DOS, "cd .." will change to the parent of the
current directory. The "CWD command successful" is the only
indication that the user's "cd" command was correctly executed; use
the "show-directory" (may be truncated to fewer characters, as shown)
command at any time to see which directory you are in.
Another "dir" command is used to find all files ending with the
characters ".act"; note the use of the "*" wildcard character. We
can now copy the file of choice (The Fair Credit Reporting Act, 1992)
by using the "get" (or "receive") command, which has the following
general format:
GET remote_file_name local_file_name
FTP opens another data transfer connection for this file transfer
purpose; note that the effective data transfer rate is 39.98 kbps.
While the "get" command allows the downloading of files from a remote
system to a local one, FTP's "put" (or "send") command allows
uploading from the local host to the remote. "Put" is typically not
available when using anonymous FTP.
Finally, we terminate the FTP connection by using the "close"
command. The user can initiate another FTP connection using the
"open" command or can leave FTP by issuing a "quit" command. "Quit"
can also be used to close a connection and terminate a session.
(It is important to note that different FTP packages have different
commands available and even those with similar names may act
differently. In the example shown here, the "show" command will
display the current directory. In another package, "show" will
display a file from the remote host at the local host. Some packages
have nothing equivalent to either of these!)
=====================================================================
SMCVAX$FTP FTP.SPIES.COM
SMCVAX.SMCVT.EDU MultiNet FTP user process 3.2(106)
Connection opened (Assuming 8-bit connections)
Username: ANONYMOUS
Password: GUEST
WIRETAP.SPIES.COM>HELP ? one of the following:
ACCOUNT AGET
APPEND APUT
ASCII ATTACH
BELL BINARY
BYE BYTE
CD CDUP
CLOSE CONFIRM
CPATH CREATE-DIRECTORY
CWD DELETE
DIRECTORY DISCONNECT
EXIT EXIT-ON-ERROR
GET HASH
HELP LCD
LDIR LOCAL-CD
LOCAL-DIRECTORY LOCAL-PWD
LOGIN LPWD
LS MDELETE
MGET MKDIR
MODE MPUT
MULTIPLE PASSWORD
PORT PROMPT-FOR-MISSING-ARGUMENTS
PROMPT-ON-CONNECT PUSH
PUT PWD
QUIT QUOTE
RECEIVE REMOTE-HELP
REMOVE-DIRECTORY RENAME
RETAIN RM
RMDIR SEND
SHOW-DIRECTORY SITE
SPAWN STATISTICS
STATUS STREAM
STRUCTURE TAKE
TENEX TYPE
USER VERBOSE
VERSION
WIRETAP.SPIES.COM>HELP TYPE
The TYPE command changes the FTP transfer type. The possible
arguments to the TYPE command are ASCII, IMAGE, BACKUP, and
LOGICAL-BYTE ASCII type is used for transferring ASCII text files.
IMAGE type is used for transferring binary files. BACKUP type is
used for transferring VAX/VMS backup savesets with 2048 byte block
size.
WIRETAP.SPIES.COM>DIR
<Opening ASCII mode data connection for /bin/ls.
total 25
drwxr-xr-x 2 9013 daemon 512 Jul 1 1993 .cap
drwxr-xr-x 4 9013 daemon 512 Jul 1 1993 About
-rw-r--r-- 1 9013 daemon 791 Apr 6 1993 About_Gopher
drwxr-xr-x 3 9013 daemon 512 Jul 12 1993 Books
drwxr-xr-x 13 9013 daemon 512 Jul 1 1993 Clinton
lrwxrwxrwx 1 root daemon 12 Feb 26 07:02 Economic_Plan
-> Gov/Economic
drwxr-xr-x 4 9013 daemon 512 Jul 1 1993 Etext
lrwxrwxrwx 1 root daemon 13 Feb 26 07:01 GAO_Reports ->
Gov/GAO-Trans
drwxr-xr-x 29 9013 daemon 1024 Feb 3 00:15 Gov
drwxr-xr-x 16 9013 daemon 512 Jul 1 1993 Library
lrwxrwxrwx 1 root daemon 9 Feb 26 06:56 NAFTA ->
Gov/NAFTA
drwxr-xr-x 2 9013 daemon 512 Jul 1 1993 Other
drwxr-xr-x 3 9013 daemon 3072 Apr 7 20:59 alt.etext
drwxr-xr-x 8 root 42 512 Jul 1 1993 ba.internet
dr-xr-xr-x 2 bin wheel 512 Jul 1 1993 bin
drwxr-xr-x 2 root daemon 512 Feb 15 06:14 dev
drwxr-xr-x 3 root wheel 512 Jul 1 1993 etc
drwxr-xr-x 11 9038 daemon 512 Dec 17 05:37 game_archive
drwx-wx-wx 3 root daemon 1024 Apr 18 02:09 incoming
drwxr-xr-x 3 root ftp 512 Oct 29 02:35 pub
drwxr-xr-x 2 root daemon 512 Jul 1 1992 tmp
drwxr-xr-x 3 root daemon 512 Jul 1 1993 usr
drwxr-xr-x 3 9013 42 1024 Jul 1 1993 waffle
<Transfer complete.
1490 bytes transferred at 4966 bps.
Run time = 10. ms, Elapsed time = 2400. ms.
WIRETAP.SPIES.COM>CD Gov
<CWD command successful.
WIRETAP.SPIES.COM>SHOW
<"/Gov" is current directory.
WIRETAP.SPIES.COM>DIR *.act
<Opening ASCII mode data connection for /bin/ls.
-rw-r--r-- 1 9013 42 32695 Dec 10 21:37 brady.act
-r--r--r-- 1 9013 42 168649 Mar 26 1993 disable.act
-r--r--r-- 1 9013 42 62602 Mar 30 1993 ecpa.act
-r--r--r-- 1 9013 42 29519 Mar 30 1993 faircredit.act
-r--r--r-- 1 9013 42 57206 Mar 30 1993 privacy.act
-r--r--r-- 1 9013 42 16261 Mar 26 1993 warpower.act
<Transfer complete.
401 bytes transferred at 7638 bps.
Run time = 0. ms, Elapsed time = 420. ms.
WIRETAP.SPIES.COM>GET faircredit.act FAIRCRDT.TXT
<Opening ASCII mode data connection for faircredit.act (29519 bytes).
<Transfer complete.
30132 bytes transferred at 39976 bps.
Run time = 40. ms, Elapsed time = 6030. ms.
WIRETAP.SPIES.COM>QUIT
<Goodbye.
SMCVAX$
=====================================================================
2.6. TELNET
TELNET [vd] is TCP/IP's virtual terminal protocol. Using TELNET, a
user connected to one host can login to another host, appearing like
a directly-attached terminal at the remote system; this is TCP/IP's
definition of a "virtual terminal." The general form of the TELNET
command is:
TELNET [ip_address | host_name] [port]
As shown, a TELNET connection is initiated when the user enters the
"TELNET" command and supplies either a "host_name" or "IP_address";
if neither are given, TELNET will ask for one once the application
begins. In addition, a specific port number can be supplied if the
user wishes to attach to a specific application at the remote host.
(Examples of this last feature are shown in Sections 2.7.2 and 2.9.)
In the example below, a user logged onto the host SMCVAX will use
TELNET to attach to a host called EMILY at the University of Vermont.
Once logged in via TELNET, the user can do anything that they could
do if they were on a directly-connected terminal or had dialed-up by
modem. The commands that are used are available on the remote system
to which we are TELNETed:
o The "dir" command lists the available files and directories.
o The "mail" command enters the MAIL system (there are no messages).
o "Pinging" the SMCVAX host shows that it is alive!
When finished, "logout" logs the user off the remote host; TELNET
automatically closes the connection to the remote host and returns
control to the local system.
=====================================================================
SMCVAX$ TELNET EMILY.EMBA.UVM.EDU
Trying... Connected to EMILY.EMBA.UVM.EDU.
University of Vermont EMBA Computer Facility
Connected to "emily"
login: HILL
Password:
hill> DIR
total 1682
drwx------ hill others 512 Dec 10 1992 Mail/
-rw------- hill others 22382 Apr 26 07:33 dos-cdev-12.hqx
drwx------ hill others 512 Jul 11 16:09 gary/
drwx------ hill others 512 Dec 10 1992 itu/
-rw------- hill others 1805 Feb 5 13:42 mbox
drwx------ hill others 1024 Dec 15 1992 misc/
-rw------- hill others 87754 Apr 26 12:56 osinet.2
-rw------- hill others 566731 May 14 08:10 quicktime-16.hqx
-rw------- hill others 128858 May 13 08:12 res-edit-tips.hqx
-rw------- hill others 110610 May 13 08:12 res-helper.hqx
drwx------ hill others 5632 Apr 23 08:51 rfc/
drwx------ hill others 512 Apr 16 09:15 xmodem/
drwx------ hill others 1024 Apr 13 16:35 zmodem/
hill> MAIL
No mail for hill
hill> PING SMCVAX.SMCVT.EDU
smcvax.smcvt.edu is alive
hill> LOGOUT
Connection closed by Foreign Host
SMCVAX$
=====================================================================
2.7. User Database Lookup Tools
2.7.1. WHOIS/NICNAME
WHOIS and NICNAME are TCP/IP applications that search databases to
find the name of network and system administrators, RFC authors,
system and network points-of-contact, and other individuals who are
registered in appropriate databases. The original NICNAME/WHOIS
protocol is described in [vf].
WHOIS may be accessed by TELNETing to an appropriate WHOIS server and
logging in as "WHOIS" (no password is required); the most common
Internet name server is located at the Internet Network Information
Center (InterNIC) at rs.internic.net. This specific database, in
particular, only contains INTERNET domains, IP network numbers, and
points of contact; policies governing the InterNIC database are
described in [vh]. The MILNET database resides at NIC.DDN.MIL and
PSI's White Pages pilot service is located at psi.com.
Optionally, many software packages contain a WHOIS interface that
automatically establishes the TELNET connection to an appropriate
server.
The accompanying dialogues shows both types of WHOIS access. In the
session below, we request information about an individual (Denis
Stratford), a specific domain (smcvt.edu), and a high level domain
(edu).
==============================================================
SMCVAX$ WHOIS STRATFORD, DENIS
Stratford, Denis (DS378) denis@@SMCVAX.SMCVT.EDU
St. Michael's College
Jemery Hall, Room 274
Winooski Park
Colchester, VT 05439
(802) 654-2384
Record last updated on 02-Nov-92.
SMCVAX$ WHOIS DOMAIN SMCVT.EDU
St. Michael's College (SMCVT-DOM)
Winooski Park
Colchester, VT 05439
Domain Name: SMCVT.EDU
Administrative Contact:
Stratford, Denis (DS378) denis@@SMCVAX.SMCVT.EDU
(802) 654-2384
Technical Contact, Zone Contact:
Goodwin, David (DG176) goodwin@SMCVAX.SMCVT.EDU
(802) 654-2220
Record last updated on 02-Nov-92.
Domain servers in listed order:
NIC.NEAR.NET 192.52.71.4
BU.EDU 128.197.27.7
NOC.CERF.NET 192.153.156.22
SMCVAX$ TELNET RS.INTERNIC.NET
Trying... Connected to RS.INTERNIC.NET, a SUN 670 running SUNOS-4.1.3
SunOS UNIX (rs) (ttyq0)
*********************************************************************
* -- InterNIC Registration Services Center --
*********************************************************************
Cmdinter Ver 1.3 Mon Mar 21 13:42:27 1994 EST
[vt102] InterNIC > WHOIS
Connected to the rs Database
InterNIC WHOIS Version: 1.0 Mon, 21 Mar 94 13:42:32
Whois: DOMAIN EDU
Education top-level domain (EDU-DOM)
Network Solutions, Inc.
505 Huntmar park Dr.
Herndon, VA 22070
Domain Name: EDU
Administrative Contact, Technical Contact, Zone Contact:
Network Solutions, Inc. (HOSTMASTER) HOSTMASTER@INTERNIC.NET
(703) 742-4777 (FAX) (703) 742-4811
Record last updated on 06-Jul-93.
Domain servers in listed order:
NS.INTERNIC.NET 198.41.0.4
AOS.ARL.ARMY.MIL 128.63.4.82, 192.5.25.82
KAVA.NISC.SRI.COM 192.33.33.24
C.NYSER.NET 192.33.4.12
TERP.UMD.EDU 128.8.10.90
NS.NASA.GOV 128.102.16.10, 192.52.195.10
NIC.NORDU.NET 192.36.148.17
NS.NIC.DDN.MIL 192.112.36.4
Would you like to see the known domains under this top-level domain?
Y
There are 1419 known sub-domains:
0.EDU Reserved Domain
1.EDU Reserved Domain
2.EDU Reserved Domain
22CF.EDU 22nd Century Foundation
3.EDU Reserved Domain
There are 1414 more matches. Show them? N
Whois: EXIT
[vt102] InterNIC > QUIT
Mon Mar 21 13:43:08 1994 EST
Connection closed by Foreign Host
SMCVAX$
==============================================================
2.7.2. KNOWBOT
KNOWBOT is an automated username database search tool that is related
to WHOIS. The Knowbot Information Service (KIS) provides a simple
WHOIS-like interface that allows users to query a number of Internet
user databases (White Pages services) all at one time. A single KIS
query will automatically search the InterNIC, MILNET, MCImail, and
PSI White Pages Pilot Project; other databases may also be included.
KNOWBOT may be accessed by TELNETing to port 185 on hosts
INFO.CNRI.RESTON.VA.US or SOL.BUCKNELL.EDU. The "help" command will
supply sufficient information to get started. The sample dialogue
below shows use of the "query" command to locate a user named Tom
Maufer; this command automatically starts a search through the
default set of Internet databases.
==============================================================
TELNET INFO.CNRI.RESTON.VA.US /PORT=185
Connected to INFO.CNRI.RESTON.VA.US, a SUN4/110 running UNIX.
Knowbot Information Service
KIS Client (V2.0). Copyright CNRI 1990. All Rights Reserved.
Please enter your email address in our guest book...
(Your email address?) > KUMQUAT@SMCVAX.SMCVT.EDU
> QUERY MAUFER, TOM
Connected to KIS server (V1.0). Copyright CNRI 1990. All Rights
Reserved.
Trying whois at ds.internic.net...
The ds.internic.net whois server is being queried:
--------------------
Maufer, Thomas A. (TAM36) tom_maufer@GSFC.NASA.GOV
NASA Goddard Space Flight Center
Center Network Environment Project
Code 520/CBSI
Greenbelt, MD 20771
(301) 286-0708 (FAX) (301) 286-4627
Record last updated on 25-Feb-93.
The rs.internic.net whois server is being queried:
No match for name "MAUFER,TOM".
The nic.ddn.mil whois server is being queried:
No match for name "MAUFER,TOM".
Trying mcimail at cnri.reston.va.us...
Trying ripe at whois.ripe.net...
Trying whois at whois.lac.net...
No match found for .MAUFER,TOM
> QUIT
KIS exiting
Connection closed by Foreign Host
SMCVAX$
==============================================================
2.7.3. NETFIND
NETFIND is another tool that may be used to locate people on the
network. NETFIND's advantage is that it searches for users by
utilizing extant tools such as Finger and SMTP, thus providing the
potential to find any users on any host without relying on databases.
For NETFIND to be successful, however, the system manager of existing
systems must set up Finger and SMTP to respond correctly to NETFIND's
queries. NETFIND is still relatively new and use will grow over
time.
NETFIND is a menu-driven, text-based system. Users need to TELNET to
an available NETFIND server. Once connected, login as "netfind"
(must be lower-case; no password required) and follow the menu
prompts. The sample dialogue below shows the search for "Tom
Maufer", who I know works at Goddard Space Flight Center ("gsfc"), a
part of NASA ("nasa gov").
The primary NETFIND server is located at the University of Colorado
in Boulder (BRUNO.CS.COLORADO.EDU). Currently available alternate
servers include:
archie.au (AARNet, Melbourne, Australia)
dino.conicit.ve (Nat. Council for Tech. & Sci. Research, Venezuela)
ds.internic.net (InterNIC Directory & DB Svcs., S. Plainfield, NJ)
eis.calstate.edu (California State University, Fullerton, CA)
hto-e.usc.edu (University of Southern California, Los Angeles)
krnic.net (Korea Network Information Center, Taejon, Korea)
lincoln.technet.sg (Technet Unit, Singapore)
malloco.ing.puc.cl (Catholic University of Chile, Santiago)
monolith.cc.ic.ac.uk (Imperial College, London, England)
mudhoney.micro.umn.edu (University of Minnesota, Minneapolis)
netfind.anu.edu.au (Australian National University, Canberra)
netfind.ee.mcgill.ca (McGill University, Montreal, Quebec, Canada)
netfind.if.usp.br (University of Sao Paulo, Sao Paulo, Brazil)
netfind.oc.com (OpenConnect Systems, Dallas, Texas)
netfind.sjsu.edu (San Jose State University, San Jose, California)
netfind.vslib.cz (Liberec University of Technology, Czech Republic)
nic.uakom.sk (Academy of Sciences, Banska Bystrica, Slovakia)
redmont.cis.uab.edu (University of Alabama at Birmingham)
==============================================================
SMCVAX$TELNET NETFIND.OC.COM
Connected to MAELSTROM.OC.COM.
SunOS UNIX (maelstrom.oc.com)
login: netfind
=================================================
Welcome to the OpenConnect Systems Netfind Server
=================================================
Top level choices:
1. Help
2. Search
3. Seed database lookup
4. Options
5. Quit (exit server)
--> 2
Enter person and keys (blank to exit) --> MAUFER GSFC NASA GOV
Please select at most 3 of the following domains to search:
0. gsfc.nasa.gov (goddard space flight center, united states
national aeronautics and space administration, greenbelt, maryland)
1. antwrp.gsfc.nasa.gov (compton gamma ray observatory
science support center, goddard space flight center, united states
national aeronautics and space administration, greenbelt, maryland)
2. enemy.gsfc.nasa.gov (compton gamma ray observatory science
support center, goddard space flight center, united states national
aeronautics and space administration, greenbelt, maryland)
3. upolu.gsfc.nasa.gov (goddard space flight center, united
states national aeronautics and space administration, greenbelt,
maryland)
Enter selection (e.g., 2 0 1) --> 0
( 1) SMTP_Finger_Search: checking domain gsfc.nasa.gov
Mail is forwarded to tom@stimpy.gsfc.nasa.gov
NOTE: this is a domain mail forwarding arrangement - so mail intended
for "maufer" should be addressed to "tom@gsfc.nasa.gov"
rather than "tom@stimpy.gsfc.nasa.gov".
( 1) SMTP_Finger_Search: checking host stimpy.gsfc.nasa.gov
------
Domain search completed. Proceeding to host search.
------
SYSTEM: kong.gsfc.nasa.gov
Login name: maufer In real life: Tom Maufer - CBSI
Directory: /vault/maufer Shell: /bin/csh
Last login Fri Sep 24, 1993 on ttypc from rocinante.gsfc.n
No unread mail
No Plan.
FINGER SUMMARY:
- The most promising email address for "maufer"
based on the above finger search is
tom@gsfc.nasa.gov.
Continue the search ([n]/y) ? --> N
Enter person and keys (blank to exit) -->
Top level choices:
1. Help
2. Search
3. Seed database lookup
4. Options
5. Quit (exit server)
--> 5
Exiting Netfind server...
Connection closed by Foreign Host
SMCVAX$
==============================================================
2.8. Information Servers
2.8.1. ARCHIE
Archie is a database server, originally developed at the Computer
Science Department of McGill University in Montreal. Its intent is
to allow users to find documents and software that reside at open
file transfer sites and have been registered with Archie; by early
1994, more than three million files at 1,500 locations had been
registered. This program has become so popular that many sites now
provide the Archie service.
Before using Archie, you must identify an appropriate server
location. The sites below all support Archie and there may be more;
most (but not all) Archie sites support the "servers" command which
lists all known Archie servers. Due to the popularity of Archie and
its high processing demands, many sites limit access to non-peak
hours and/or limit the number of simultaneous Archie users.
Available Archie sites include:
archie.au* 139.130.4.6 Australia
archie.edvz.uni-linz.ac.at* 140.78.3.8 Austria
archie.univie.ac.at* 131.130.1.23 Austria
archie.uqam.ca* 132.208.250.10 Canada
archie.funet.fi 128.214.6.100 Finland
archie.th-darmstadt.de* 130.83.22.60 Germany
archie.ac.il* 132.65.6.15 Israel
archie.unipi.it* 131.114.21.10 Italy
archie.wide.ad.jp 133.4.3.6 Japan
archie.hana.nm.kr* 128.134.1.1 Korea
archie.sogang.ac.kr* 163.239.1.11 Korea
archie.uninett.no* 128.39.2.20 Norway
archie.rediris.es* 130.206.1.2 Spain
archie.luth.se* 130.240.18.4 Sweden
archie.switch.ch* 130.59.1.40 Switzerland
archie.ncu.edu.tw* 140.115.19.24 Taiwan
archie.doc.ic.ac.uk* 146.169.11.3 United Kingdom
archie.unl.edu 129.93.1.14 USA (NE)
archie.internic.net* 198.48.45.10 USA (NJ)
archie.rutgers.edu* 128.6.18.15 USA (NJ)
archie.ans.net 147.225.1.10 USA (NY)
archie.sura.net* 128.167.254.179 USA (MD)
Note: Sites marked with an asterisk "*" run archie version 3.0.
Archie servers may be accessed using TELNET. When TELNETing to an
Archie site, login as "archie" (you MUST use lower case); no password
will be required. Some packages now supply an Archie interface that
hides this step; you can attach to a pre-configured Archie server
merely by typing "ARCHIE".
Once connected, the "help" command assists users in obtaining more
information about using Archie. Two more useful Archie commands are
"prog", used to search for files in the database, and "whatis", which
searches for keywords in the program descriptions.
In the accompanying dialogue, the "set maxhits" command is used to
limit the number of responses to any following "prog" commands; if
this is not done, the user may get an enormous amount of information!
In this example, the user issues a request to find entries related to
"mpeg", ISO's Moving Pictures Experts Group video compression
algorithm. The first two responses indicate a directory named "mpeg"
at academic sites in Australia (...edu.au). The next three responses
show other directories with this name at sites in Sweden (...se).
Armed with this information, a user can use anonymous FTP to examine
these directories and download files.
The next request is for files with "security" as a keyword
descriptor. These responses can be used for subsequent "prog"
commands.
Exit archie using the "exit" command. At this point, TELNET closes
the connection and control returns to the local host.
Current information about Archie can be obtained by sending e-mail to
Bunyip Information Systems in Canada (archie-info@bunyip.com).
Archie client software is not required to use Archie, but can make
life a little easier; some such software can be found in the
"/pub/archie/" path at host "ftp.cs.widener.edu".
=====================================================================
SMCVAX$ TELNET 129.93.1.14
Trying... Connected.
SunOS UNIX (crcnis2)
login: archie
SunOS Release 4.1.2 (CRCNIS2) #1: Wed Dec 16 12:10:12 EST 1992
Welcome to the ARCHIE server at the University of Nebraska - Lincoln
unl-archie> HELP
Currently, the available help topics are:
about - a blurb about archie
bugs - known bugs and undesirable features
bye - same as "quit"
email - how to contact the archie email interface
exit - same as "quit"
help - this message
list - list the sites in the archie database
mail - mail output to a user
nopager - *** use 'unset pager' instead
pager - *** use 'set pager' instead
prog - search the database for a file
quit - exit archie
set - set a variable
show - display the value of a variable
site - list the files at an archive site
term - *** use 'set term ...' instead
unset - unset a variable
whatis - search for keyword in the software description database
For information on one of these topics type: help <topic>
unl-archie> SET MAXHITS 5
unl-archie> PROG MPEG
# matches / % database searched: 5 / 0%
Host csc.canberra.edu.au
Location: /pub/motif
DIRECTORY drwxr-xr-x 512 Dec 4 03:55 mpeg
Host daneel.rdt.monash.edu.au
Location: /pub/images
DIRECTORY drwxrwxr-x 512 Nov 30 16:44 mpeg
Host ftp.luth.se
Location: /pub/graphics/animation
DIRECTORY drwxrwxr-x 1536 Jul 24 1993 mpeg
Host ftp.sunet.se
Location: /pub/graphics
DIRECTORY drwxrwxr-x 1024 Dec 11 04:36 mpeg
Host maeglin.mt.luth.se
Location: /CSCW/multimedia
DIRECTORY drwxr-xr-x 512 Oct 5 15:23 mpeg
unl-archie> WHATIS SECURITY
RFC 1037 Greenberg, B.; Keene, S. NFILE - a file access
protocol. 1987 December; 86 p.
RFC 1038 St. Johns, M.
Draft revised IP security option. 1988 January; 7 p.
cops System Security analysis tool
forktest Find security holes in shell-escapes
kerberos Host security package
safe-mkdir mkdir() and security hole *****FIX****
unl-archie> EXIT
Connection closed by Foreign Host
SMCVAX$
=====================================================================
2.8.2. GOPHER
Gopher is a distributed document search and retrieval protocol for
the Internet. The Internet Gopher protocol was developed by the
Microcomputer Center at the University of Minnesota in 1991 and is
described in [vj].
Gopher is a hierarchical, menu-based system and users need some type
of client software to use Gopher servers. In many cases, users can
access Gopher by TELNETing to a valid Gopher location that provides
Gopher client support locally; in this case, the client typically
provides a text-based, menu interface. The number of Gopher sites is
growing rapidly; as the dialogue below shows, most Gopher sites have
a menu item that will allow you to identify other Gopher sites. If
using TELNET, login with the username "gopher" (this MUST be in
lowercase); no password is required.
If using a menu-based interface, the user merely follows the prompts
as shown in the dialogue below. Initially, the main menu will
appear; selecting item 1 causes Gopher to seize the "Information
about Gopher" menu. This menu also has sub-menus, which are not
shown here. To quit the program at any time, press the "q" key; "?"
and "u" will provide help or go back up to the previous menu,
respectively. Users may also search for strings within files (using
the "/" command) or download the file being interrogated (using the
"D" command).
The Gopher server at is.internic.net has a tremendous amount of
information for the new user, including lists of frequently asked
questions and pointers to various Internet discussion lists. That is
the site shown in the sample dialogue below. After establishing a
connection and logging on, a root menu is displayed. Item 7 is
titled "Getting Started on the Internet," we move to that menu merely
by entering a "7" or by moving the arrow (-->) down to the desired
entry (using the <DOWN-ARROW> key on the keyboard) and hitting
<ENTER>. Quit the program by typing "q" at any menu.
Further information about Gopher can be obtained by contacting the
Internet Gopher Team at the University of Minnesota in Minneapolis
(gopher@boombox.micro.umn.edu). This is also the site of the first
Gopher server (consultant.micro.umn.edu). A Gopher-related
discussion list is maintained at gopher-news@boombox.micro.umn.edu
(see Section 2.10.1 for information on subscribing to discussion
lists). More information on Gopher clients can be found in the
Gopher Frequently Asked Questions (FAQ) file, which can be accessed
by anonymous ftp from path "/pub/usenet/news.answers/gopher-faq" at
the host "rtfm.mit.edu". This FAQ also lists sources of a number of
Gopher clients for a wide range of hardware/software platforms.
=====================================================================
SMCVAX$ TELNET
SMCVAX.SMCVT.EDU MultiNet TELNET-32 3.1(88)
TELNET> OPEN IS.INTERNIC.NET
Trying... Connected to IS.INTERNIC.NET.
SunOS UNIX (is)
login: gopher
Welcome to the InterNIC Information Service Gopher
Internet Gopher Information Client v2.0.12
InterNIC Information Services InfoSource
--> 1. Welcome to the InfoSource/
2. Infosource Update <As of 11/9/93>
3. InfoSource Table of Contents
4. Getting Connected to the Internet/
5. InterNIC Store/
6. About InterNIC Information Services/
7. Getting Started on the Internet/
8. Internet Information for Everybody/
9. Just for NICs/
10. NSF, NREN, National Information Infrastructure Information/
11. Beyond InterNIC: Virtual Treasures of the Internet/
12. Top Documents Requested at InterNIC IS/
13. Searching the InfoSource by Keyword/
Press ? for Help, q to Quit Page: 1/1
7
Internet Gopher Information Client v2.0.12
Getting Started on the Internet
--> 1. What is the Internet/
2. Fact Sheet: Getting Started on the Internet
3. Getting Connected/
4. Things to Do on the Internet/
5. Learning to Use the Network/
6. Glossary of Internet Terms
7. Bibliography
8. "FYI" Series of Documents/
9. "RFC" Series of Documents/
10. Internet Names and Addresses
11. Internet Domain Name System
12. Frequently Asked Questions (FAQs)/
Press ? for Help, q to Quit Page: 1/1
Q
Really quit (y/n) ?
Y
Connection closed by Foreign Host
SMCVAX$
=====================================================================
2.8.3. Other Information Servers
There are a number of other information servers that are growing in
popularity and use, although Archie and Gopher remain the two premier
information access and retrieval tools. The problem with being
blessed with so much information from Archie, Gopher, and other
sources is exactly that -- too much information. To make it easier
for users to locate the system on which their desired information
resides, a number of other tools have been created.
Veronica (Very Easy Rodent-Oriented Net-wide Index to Computerized
Archives) was developed at the University of Nevada as an adjunct to
Gopher. Whereas Gopher is designed to search a single database at a
time, Veronica performs a keyword search on all of the Gopher sites
that it has knowledge of and access to. When a user selects an item
from the menu of a Veronica search, "sessions" are automatically
established with the appropriate Gopher servers, all transparent to
the user.
Archie and Gopher are primarily used for the indexing of text-based
files. The World Wide Web (WWW or W3) Project is designed to combine
aspects of information retrieval with multimedia communications. The
WWW Project is intended to allow users to access information in many
different types of formats, including text and image. WWW treats
all searchable Internet files as hypertext documents, allowing the
user to create non-linear, non-hierarchical linkages between data
points. The primary WWW site is at the CERN Institute in
Switzerland, and may be accessed via Telnet at "nxoc01.cern.ch". The
user will be automatically logged in and a help menu can be displayed
by entering the "h" command. WWW sources and additional information
may be accessed via anonymous FTP from the "/pub/WWW" directory at
"info.cern.ch" or the "/Web/" directory at "ftp.ncsa.uiuc.edu".
The Wide Area Information Server (WAIS, pronounced "ways") was
initiated as a joint venture between Apple Computer, Dow Jones, and
KMPG Peat Marwick, and Thinking Machines Corp. WAIS provides a
single interface through which a user can access many different
information databases. The user interface allow a query to be
formulated in English and the WAIS server will automatically choose
the appropriate databases to search. Further information about WAIS
can be obtained by reading the WAIS FAQ, available from host
"rtfm.mit.edu" in file "/pub/usenet/news.answers/wais-faq".
[[draft paragraph... more info to follow...]]
Mosaic is a tool that can be used to navigate through the WWW.
Mosaic supports multimedia presentations that are available on the
Web, information that might include text, image, or video. Mosaic
provides a uniform mechanism for finding the location of information,
as well as determining the data type, presentation method, and
linkages to other information. Mosaic sites are referenced in the
form:
http://"host_name"/"path"/"filename".html
The "http" indicates that this is the default home page, where the
Mosaic application will start; the ".html" file extension indicates
use of the HyperText Multimedia Language. A large number of Mosaic
clients are available at "ftp.ncsa.uiuc.edu".
2.9. Electronic Mail and SMTP
Electronic mail, or e-mail, is the biggest single use of the
Internet. The Simple Mail Transfer Protocol (SMTP) [vl] is the mail
transfer application used across TCP/IP-based networks, although most
users never use SMTP directly; instead they use their host system's
native mail application, which uses SMTP services. Because most end
users do not directly use SMTP and they do not usually write their
own SMTP gateway software, this section describes SMTP only for
completeness and to compare SMTP to some MAIL software.
Native SMTP is neither easy to use, intuitive, nor fast. It is, on
the other hand, simple and does provide the majority of the basic
mail services that users demand. In the dialogue below, user KUMQUAT
at host SMCVAX wants to send mail to user HILL at host EMILY. SMTP
at EMILY is accessed by opening a TELNET connection, specifying
TCP/IP port 25, a port that is always associated with the SMTP
application. Note that after TELNETing to port 25, EMILY completes
the connection without requesting a login or password.
SMTP's HELO command is used to tell EMILY which host it is being
accessing from; EMILY responds politely, as do most SMTP hosts! We
are now ready to send mail.
The sender uses the MAIL FROM: command to identify themselves. The
RCPT TO: command is used to identify the intended recipient; any
number of intended receivers may be specified, and SMTP will verify
whether the specified users are known or not. Note that these
commands require that the user identifier be placed within angle
brackets (<>).
When ready to send the message, the DATA command is used. The sender
signals the end of the message by typing a line that contains nothing
but a period (.). The user could now send more messages to users at
this remote host or exit SMTP using QUIT. In the dialogue below, a
second message is sent to the same recipient using the local host
system's native e-mail, for comparison purposes only.
E-mail is a tremendously important topic and much more detailed
information may be found in [vr].
=====================================================================
SMCVAX$ TELNET EMILY.UVM.EDU /PORT=25
Trying... Connected to EMILY.EMBA.UVM.EDU.
220 emily.emba.uvm.edu Sendmail 5.65/1.07 ready at Mon, 21 Mar 1994
17:38:54 -0400
HELO SMCVAX.SMCVT.EDU
250 Hello smcvax.smcvt.edu, pleased to meet you
MAIL FROM: <KUMQUAT>
250 <kumquat>... Sender ok
RCPT TO: <HILL@EMILY.UVM.EDU>
250 <hill@emily.uvm.edu>... Recipient ok
DATA
354 Enter mail, end with "." on a line by itself
HI. YES, TELNET AND SMTP SEEM OK NOW.
THANKS...
/KESS
.
250 Ok
QUIT
221 emily.emba.uvm.edu closing connection
Connection closed by Foreign Host
SMCVAX$ MAIL
MAIL> SEND
To: IN%"HILL@EMILY.UVM.EDU"
Subj: CONNECTION STATUS...
Enter your message below. Press CTRL/Z when complete, CTRL/C to quit:
HI. YES, TELNET AND SMTP SEEM OK NOW. (#2)
THANKS...
/KESS
^Z
Exit
MAIL> EXIT
SMCVAX$
=====================================================================
2.10. Getting More Information On-line...
2.10.1. Discussion Lists
Among the most useful features of the Internet are the discussion
lists that have become available to allow individuals to discuss
topics of mutual concern. Discussion list topics range from SCUBA
diving and home brewing of beer to AIDS research and data
communications. Several, naturally, deal specifically with the
Internet, TCP/IP protocols, and the impact of new technologies.
Most of the available lists are "unmoderated." This means that
anyone can send a message to the list's central repository and the
message will then be automatically forwarded to all subscribers of
the list. These lists provide very fast turn-around between
submission of a message and delivery, but often results in a lot of
messages. A "moderated" list has an extra step; a human list
moderator examines all messages before they are forwarded to ensure
that the messages are appropriate to the list and not needlessly
inflammatory!
2.10.1.1. Internet Discussion Lists
A list of the known interest groups may be found by Gophering to
is.internic.net. Follow the menu path "Getting Started on the
Internet" (item #7), "Things to Do on the Internet" (4), "Resources"
(1), and "Interest Group Mailing Lists (List of Lists)" (3). Along
the way, you will find another wealth of information. The "list of
lists" file may also be downloaded using anonymous FTP from
is.internic.net; use the file name "infosource/getting-
started/things-to-do-internet/resource-lists/interest-groups".
Alternatively, send an e-mail message to "MAIL-SERVER@NISC.SRI.COM",
leave the "Subject:" field blank, and place the line "send
INTEREST-GROUPS" in the main body of the message. Be careful if you
download this file; it is nearly 1.4 MB is size, listing over 800
lists!
Most Internet list names are of the form:
list_name@host_name
The common convention when users want to subscribe, unsubscribe, or
handle any other administrative matter, is to send a message to:
list_name-REQUEST@host_name
Not every list follows this exact convention, but it is a safe bet if
you don't have better information!
2.10.1.2. USENET
USENET, also known as NETNEWS, is another information source with its
own set of special interest mailing lists. USENET originated on UNIX
systems but has migrated to many other types of hosts. While the
USENET lists are accessible from Internet sites, the host must have
appropriate software to be able to read the USENET feed. Users will
have to check with their system administrator to find out what USENET
lists are locally available. USENET is rapidly growing in popularity
and there are more than 400 discussion groups available through
USENET.
USENET newsgroups use names that are hierarchical in nature, somewhat
similar to the Internet address name format. The first part of the
name, called the "hierarchy", provides an indication about the
general subject area. There are two types of hierarchies, called
"mainstream" and "alternative".
Usenet mainstream hierarchies are established by a process that
requires the approval of Usenet members. Most sites that receive a
NETNEWS feed receive all of these hierarchies, which include:
comp Computers
misc Miscellaneous
news Network news
rec Recreation
sci Science
soc Social issues
talk Various discussion lists
The alternative hierarchies include lists that may be set up by any
site that has the know how, server software, and disk space. These
lists are not formally part of Usenet and, therefore, may not be
received by all sites getting NETNEWS. The alternative hierarchies
include:
alt Alternate miscellaneous discussion lists
bionet Biology, medicine, and life sciences
bit BITNET discussion lists
biz Various business-related discussion lists
ddn Defense Data Network
gnu GNU lists
ieee IEEE information
info Various Internet and other networking information
k12 K-12 education
u3b AT&T 3B computers
vmsnet Digital's VMS operating system
These 18 Usenet hierarchies comprise more than 2,300 discussion
lists. A list of these groups may be found at host "rtfm.mit.edu",
in the path "/pub/usenet/news.answers"; see the "active-newsgroups"
and "alt-hierarchies" subdirectories.
There is often some overlap between USENET and Internet discussion
lists. Many individuals join both lists (if possible) in these
circumstances or, often, there is cross-posting of messages. Some
USENET lists are forwarded onto the Internet by an individual site to
provide access to those users who do not have USENET available.
Users with access to Internet e-mail but not Usenet may still post
messages to a Usenet list. First, replace the periods in the Usenet
discussion list name to hyphens (e.g., the folk music discussion
list, "rec.music.folk", would become "rec-music-folk"). Then, send
an e-mail message to:
newsgroup_name@CS.UTEXAS.EDU
Finally, Usenet news may be accessed through Gopher. Connect to
"gopher.msu.edu" using the path "News & Weather", "USENET News" or
"gopher.bham.ac.uk" using the path "Usenet News Reader".
2.10.1.3 BITNET/EARN
Another important set of discussion groups is maintained using a
program called LISTSERV. LISTSERV is a service provided widely on
BITNET and EARN, although it is also available to Internet users.
LISTSERV commands are placed in the main body of e-mail messages sent
to an appropriate mail server location. To find out what lists are
available, send a message to LISTSERV@BITNIC.EDUCOM.EDU with the
command "list global" in the main body of the message; whatever you
place in the "Subject" field: will be ignored.
Once you have found a list of interest, you can send a message to the
appropriate address with any appropriate command, including:
HELP Get help & a list of commands
SUBSCRIBE list_name your_full_name Subscribe to a list
UNSUBSCRIBE list_name Unsubscribe from a list
INDEX Get a list of LISTSERV files
GET file_name Obtain a file from the server
2.10.2. Request for Comments (RFCs)
To fully understand what is going on within the Internet community,
users might wish to obtain the occasional Request for Comments, or
RFC. RFCs are the body of literature comprising Internet protocols,
standards, research questions, humor (especially those dated 1
April), and general information. Each RFC is uniquely issued a 4-
digit number which is never reused or reissued; if a document is
revised, it is given a new RFC number and the old RFC is said to be
"obsoleted." Announcements are sent to the RFC-DIST mailing list
whenever a new RFC is issued; anyone may join this list by sending e-
mail to rfc-request@nic.ddn.mil.
RFCs may be obtained through the mail, but it is easier and faster to
get them on-line. Detailed information on how to do this may be
obtained by using RFC-INFO, an e-mail-based service to help users
locate and retrieve RFCs, Internet Monthly Reports, and FYI
documents. To use the service, send e-mail to rfc-info@isi.edu and
leave the "Subject:" field blank. Commands go in the main body of
the message:
HELP (Help file)
HELP: ways_to_get_rfcs (Help file on how to get RFCs)
RETRIEVE: RFC
Doc-ID: RFCxxxx (Retrieve RFC xxxx)
LIST: RFC (List all RFCs...)
[options] (...[matching the following options])
KEYWORDS: xxx (Title contains string "xxx")
AUTHOR: xxx (Written by "xxx")
ORGANIZATION: (Issued by company "xxx")
DATED-AFTER: mmm-dd-yyyy
DATED-BEFORE: mmm-dd-yyyy
OBSOLETES: RFCxxxx (List RFCs obsoleting RFC xxxx)
To get an RFC on-line without using RFC-INFO, you need two things;
namely, the Internet address of an RFC repository and the RFC number.
The primary RFC repositories throughout the world include those
listed in Table 1. The RFC index, or a specific reference for an
RFC, will indicate whether the RFC exists in ASCII text or PostScript
format; by convention, all RFCs are available in ASCII while some are
also available in PostScript where that adds more information or
clarity. The instructions below show how to get the index; be aware
that this file is very large, containing the citing for over 1600
documents.
---------------------------------------------------------------------
TABLE 1. Some of the RFC Repositories.
REGION HOST ADDRESS DIRECTORY E-MAIL SERVER
U.S. venera.isi.edu in-notes rfc-index@isi.edu
U.S. wuarchive.wustl.edu info/rfc (none)
U.S. nic.ddn.mil rfc service@nic.ddn.mil
U.S. nisc.jvnc.net rfc sendrfc@jvnc.net
U.K. src.doc.ic.ac.uk rfc info-server@doc.ic.ac.uk
Europe funet.fi rfc archive-server@funet.fi
Pacific munnari.oz.au rfc (none)
---------------------------------------------------------------------
There are two mechanisms for on-line retrieval of RFCs, namely, by
using an electronic mail server or via anonymous FTP. To obtain RFCs
using the electronic mail server, send an e-mail message to an
appropriate mail server listed in Table 1 and leave the "Subject:"
field blank. In the main body of the message, use one or more of the
following commands (where "dir" is replaced with the directory name
as shown in Table 1):
SEND HELP (Help file)
SEND dir/RFC-INDEX (RFC Index)
SEND dir/RFCxxxx.TXT (ASCII version of RFC xxxx)
SEND dir/RFCxxxx.PS (PostScript version of RFC xxxx)
To obtain RFCs using anonymous FTP, login to one of the RFC servers
listed in Table 1 with the username "anonymous" and password "guest".
After logging in, change to the appropriate RFC directory (as shown
in Table 1) using the "cd" command. To obtain a particular file, use
the "get" command:
GET RFC-INDEX.txt local_name (RFC Index)
GET RFCxxxx.txt local_name (ASCII version of RFC XXXX)
GET RFCxxxx.ps local_name (PostScript version of RFC XXXX)
=====================================================================
SMCVAX$ MAIL
MAIL> SEND
To: IN%"SERVICE@NIC.DDN.MIL"
Subject:
Enter your message below. Press CTRL/Z when complete, CTRL/C to quit:
SEND RFC/RFC1594.TXT
^Z
MAIL> EXIT
SMCVAX$ FTP VENERA.ISI.EDU
Username: ANONYMOUS
Password:
VENERA.ISI.EDU> CD IN-NOTES
VENERA.ISI.EDU> GET RFC1594.TXT RFC-1594.TXT
VENERA.ISI.EDU> EXIT
SMCVAX$
=====================================================================
2.10.3 Internet Standards
RFCs describe many aspects of the Internet. Over the years, however,
so many specifications of various protocols had been written that it
was not always clear as to which documents represented standards for
the Internet. For that reason, a subset of RFCs have been designated
as STDs to identify the Internet standards.
Unlike RFC numbers that are never reused, STD numbers always refer to
the latest version of the standard. UDP, for example, would be
completely identified as "STD-6/RFC-768." Note that STD numbers
refer to a standard, which is not necessarily a single document; an
STD, therefore, might refer to several RFCs. STD 19, for example, is
the NetBIOS Service Protocols standard and comprises RFCs 1001 and
1002; a complete citation for this standard would be "STD-19/RFC-
1001/RFC-1002." STDs are obtained in the same way as RFCs.
The availability of new STDs is announced on the RFC-DIST mailing
list. STD-1 [vn] always refers to the latest list of "Internet
Official Protocol Standards". The Internet standards process is
described more in [vo] and the STD notes are explained in [vq].
2.10.4 Getting FYIs
The For Your Information (FYI) series of RFCs provides Internet users
with information about many topics related to the Internet. FYI
topics range from historical to explanatory to tutorial, and are
aimed at the wide spectrum of users that access the Internet. The
FYI series includes answers to frequently asked questions by both
beginning and seasoned users of the Internet, an annotated
bibliography of Internet books, and an explanation of the DNS.
Like the STDs, an FYI number always refers to the latest version of
an FYI. FYI 4, for example, refers to the answers to commonly asked
questions by new Internet users; its complete citation would be "FYI-
4/RFC-1594."
FYIs can be obtained as RFCs via anonymous FTP from any RFC
repository. In addition, some RFC sites (such as NIC.DDN.MIL),
provide an FYI directory so that FYI documents can be found using the
path /FYI/mm.TXT, where "mm" refers to the FYI number. FYIs can also
be obtained by an automatic mail service; send an e-mail message to
SERVICE@NIC.DDN.MIL and place the command "SEND FYI/FYImm.TXT" in the
main body of the message.
The availability of new FYIs is announced on the RFC-DIST mailing
list. The FYI notes are explained in FYI-1 [vs].
2.10.5. Perusing the Internet...
This RFC is intended to provide the reader with the most rudimentary
ability to use the utilities that are provided by TCP/IP and the
Internet. By now, it is clear that the knowledge and ability of the
user is one of the only limits to what can be accomplished.
The next step after basic use of the tools is to explore the nooks
and crannies of the network. Several software tools are available to
help users in this quest. Among them are:
o Merit Computer Center (Ann Arbor, MI) offers "Cruise of the
Internet" software for Macs and PCs that can display 256 colors.
The software is available for no cost from the host nic.merit.edu.
For more information, read the READ.ME file and/or contact
cruise2feedback@merit.edu.
o A "Tour of the Internet" is available from BBN Systems and
Technologies (Cambridge, MA) for Macintosh system 6.0.5 or higher
equipped with HyperCard 2. The software is available by anonymous
FTP in the directory internet-tour on the host nnsc.nsf.net. For
more information, contact nnsc@nnsc.nsf.net or call BBN at +1 617-
873-3400.
Several RFCs also provide invaluable information about finding things
on the Internet. One of the best such sources is FYI 10/RFC 1402,
titled "There's Gold in them thar Networks! -or- Searching for
Treasure in all the Wrong Places" [vt], an excellent guide for
someone who wants to look around the Internet for a wide range of
material. Other good sources are the "Hitchhiker's Guide to the
Internet" (RFC 1118) [vm] and the "Guide to Network Resource Tools"
(FYI 23/RFC 1580) [vv]. Answers to frequently asked questions by
both new and experienced users of the Internet may be found in FYI
4/RFC 1594 [vx] and FYI 7/RFC 1207 [vz], respectively.
In addition, more books and specialized articles came out about the
Internet in 1993 than in all previous years (squared!). Some of them
are directly related to finding your way around or finding things on
the Internet, including:
o "The Internet Directory" by Eric Braun [wa]
o "The PC Internet Tour Guide" by Michael Fraase [ap]
o "Navigating the Internet" by Mark Gibbs and Richard Smith [wc]
o "The Internet Navigator" by Paul Gilster [wo]
o "The Internet Yellow Pages" by Harley Hahn and Rick Stout [aq]
o "Zen and the Art of the Internet" by Brendan Kehoe [we]
o "The Whole Internet User's Guide & Catalog" by Ed Krol [wg]
o "Users' Directory of Computer Networks" edited by Tracy LaQuey [xa]
o "INTERNET: Getting Started" by April Marine, Susan Kirkpatrick,
Vivian Neou, and Carol Ward [wi]
o "Finding it on the Internet: The Next Challenge for Librarianship"
by Brian Nielsen [wk]
A much more comprehensive list of Internet-related books may be found
in RFC 1463/FYI 19 [az].
Finally, Carl Malamud has written a delightful book called "Exploring
the Internet: A Technical Travelogue" [wm], chronicling not the
Internet as much as the people who use it. This book will not teach
you how to perform an anonymous FTP file transfer nor how to use
Gopher, but provides insights that no mere statistics can convey.
2.10.6 Getting Connected
This document is based upon the premise that "access to the Internet"
means more than just electronic mail. For this guide, "access to the
Internet" means access to the complete suite of TCP/IP tools and
utilities, including some or all of the ones listed above.
There are a number of ways in which users can access the Internet,
either as an individual or a company over dial-up or leased lines
through a regional or national Internet access provider. This RFC
will not suggest any particular method nor carrier; this will not be
an issue for most end-users anyway. There are a variety of sources
available that identify the different access providers; an on-line
list is available via Gopher at "is.internic.net". Optionally, send
an e-mail message to "mail-server@nisc.sri.com", leave the subject
line blank, and place one or both of the following commands in the
main body of the message:
send INTERNET-ACCESS-PROVIDERS-NON-US.TXT
send INTERNET-ACCESS-PROVIDERS-US.TXT
3. Acronyms and Abbreviations
ARP Address Resolution Protocol
ASCII American Standard Code for Information Interchange
BITNET Because It's Time Network
DDN Defense Data Network
DNS Domain Name System
EARN European Academic and Research Network
FAQ Frequently Asked Questions list
FTP File Transfer Protocol
FYI For Your Information series of RFCs
ICMP Internet Control Message Protocol
IP Internet Protocol
ISO International Organization for Standardization
NIC Network Information Center
NICNAME Network Information Center name service
NSF National Science Foundation
NSFNET National Science Foundation Network
RFC Request For Comments
SMDS Switched Multimegabit Data Service
SMTP Simple Mail Transfer Protocol
STD Standards series of RFCs
TCP Transmission Control Protocol
TTL Time-To-Live
WAIS Wide Area Information Server
W3 World Wide Web
WWW World Wide Web
4. Security Considerations
Security issues are not discussed in this memo.
5. Acknowledgements
Our thanks are given to all sites where we ftp'ed, telnet'ed,
gopher'ed, and otherwise used system resources. Our particular
thanks are given to St. Michael's College in Colchester, Vermont
(smcvax.smcvt.edu).
6. References
[vj] Anklesaria, F., M. McCahill, P. Lindner, D. Johnson, D. Torrey,
and B. Alberti, "The Internet Gopher Protocol", RFC 1436,
University of Minnesota, March 1993.
[vv] EARN Staff, "Guide to Network Resource Tools", FYI 23, RFC 1580,
March 1994.
[vf] Harrenstien, K., M. Stahl, and E. Feinler, "NICNAME/WHOIS", RFC
954, SRI, October 1985.
[az] Hoffman, E. and L. Jackson, "FYI on Introducing the Internet-- A
Short Bibliography of Introductory Internetworking Readings", RFC
1463, FYI 19, xxx, May 1993.
[vo] Internet Architecture Board, Internet Engineering Steering Group,
"The Internet Standards Process -- Revision 2", RFC 1602, March
1994.
[vm] Krol, E., "Hitchhiker's Guide to the Internet", RFC 1118,
University of Illinois, September 1989.
[vz] Malkin, G., A. Marine, and J. Reynolds, "FYI on Questions and
Answers: Answers to Commonly Asked 'Experienced Internet User'
Questions", FYI 7, RFC 1207, FTP Software, SRI, USC/Information
Sciences Institute, February 1991.
[vs] Malkin, G.S. and J.K. Reynolds, "F.Y.I. on F.Y.I.: Introduction
to the F.Y.I. notes", FYI 1, RFC 1150, Proteon, USC/Information
Sciences Institute, March 1990.
[vz] Marine, A., J. Reynolds, and G. Malkin, "FYI on Questions and
Answers - Answers to Commonly asked 'New Internet User'
Questions", FYI 4, RFC 1594, NASA Ames Research Center,
USC/Information Sciences Institute, Xylogics, March, 1994.
[vt] Martin, J., "There's Gold in them thar Networks! Searching for
Treasure in all the Wrong Places", FYI 10, RFC 1402, Ohio State
University, January 1993.
[vn] Postel, J., Editor, "Internet Official Protocol Standards", STD
1, RFC 1600, Internet Architecture Board, March 1994.
[vq] Postel, J., "Introduction to the STD Notes", RFC 1311,
USC/Information Sciences Institute, March 1992.
[vl] Postel, J., "Simple Mail Transfer Protocol", STD 10, RFC 821,
USC/Information Sciences Institute, August 1982.
[vb] Postel, J. and J. Reynolds, "File Transfer Protocol (FTP), STD 9,
RFC 959, USC/Information Sciences Institute, October 1985.
[vd] Postel, J. and J. Reynolds, "TELNET Protocol Specification", STD
8, RFC 854, USC/Information Sciences Institute, May 1983.
[tt] Socolofsky, T.J. and C.J. Kale, "TCP/IP Tutorial", RFC 1180,
Spider Systems Ltd., January 1991.
[vh] Williamson, S., "Transition and Modernization of the Internet
Registration Service", RFC 1400, Network Solutions, Inc., March
1993.
[uu] Zimmerman, D., "The Finger User Information Protocol", RFC 1288,
Rutgers University, December 1991.
[wa] Braun, E. "The Internet Directory". New York: Fawcett Columbine,
1994.
[za] Comer, D. "Internetworking with TCP/IP, Vol. I: Principles,
Protocols, and Architecture", 2/e. Englewood Cliffs (NJ):
Prentice-Hall, 1991.
[zb] Feit, S. "TCP/IP". New York: McGraw-Hill, 1993.
[ap] Fraase, M. "The PC Internet Tour Guide." Chapel Hill (NC):
Ventana Press, 1994.
[wc] Gibbs, M. and R. Smith. "Navigating the Internet". Carmel (IN):
SAMS, 1993.
[wo] Gilster, P. "The Internet Navigator". New York: John Wiley &
Sons, 1993.
[aq] Hahn, H. and R. Stout. "The Internet Yellow Pages". Berkeley
(CA): Osborne McGraw-Hill, 1994.
[we] Kehoe, B. "Zen and the Art of the Internet". Englewood Cliffs
(NJ): Prentice-Hall, 1993.
[wg] Krol, E. "The Whole Internet User's Guide & Catalog".
Sebastopol (CA): O'Reilly & Associates, 1992.
[xa] LaQuey, T., Editor. "Users' Directory of Computer Networks".
Bedford (MA): Digital Press, 1990.
[wm] Malamud, C. "Exploring the Internet: A Technical Travelogue".
Englewood Cliffs (NJ): PTR Prentice Hall, 1992.
[wi] Marine, A., S. Kirkpatrick, V. Neou, and C. Ward. "INTERNET:
Getting Started". Englewood Cliffs (NJ): PTR Prentice Hall,
1993.
[wk] Nielsen, B. "Finding it on the Internet: The Next Challenge for
Librarianship." Database, Vol. 13, October 1990, pp. 105-107.
[vr] Rose, M. "THE INTERNET MESSAGE: Closing the Book With Electronic
Mail". Englewood Cliffs (NJ): PTR Prentice Hall, 1993.
7. Authors' Address
Gary C. Kessler
Hill Associates
17 Roosevelt Highway
Colchester, VT 05446
Phone: +1 802-655-8633
Fax: +1 802-655-7974
EMail: kumquat@smcvax.smcvt.edu
Steven D. Shepard
Hill Associates
17 Roosevelt Highway
Colchester, VT 05446
Phone: +1 802-655-8646
Fax: +1 802-655-7974
EMail: sshepard@emily.emba.uvm.edu
``INTERNET-DRAFT'' Expires: 5 December 1994 ``INTERNET-DRAFT''
