|Title||FYI on Questions and Answers - Answers to Commonly asked "New
Internet User" Questions
|Author||A. Marine, J. Reynolds, G. Malkin
Network Working Group A. Marine
Request for Comments: 1594 NASA NAIC
FYI: 4 J. Reynolds
Obsoletes: 1325 ISI
Category: Informational G. Malkin
FYI on Questions and Answers
Answers to Commonly asked "New Internet User" Questions
Status of this Memo
This memo provides information for the Internet community. This memo
does not specify an Internet standard of any kind. Distribution of
this memo is unlimited.
This FYI RFC is one of two FYI's called, "Questions and Answers"
(Q/A), produced by the User Services Working Group of the Internet
Engineering Task Force (IETF). The goal is to document the most
commonly asked questions and answers in the Internet.
New Questions and Answers
In addition to updating information contained in the previous version
of this FYI RFC, the following new questions have been added:
Questions about Internet Organizations and Contacts:
What is the InterNIC?
Questions About Internet Services:
What is gopher?
What is the World Wide Web? What is Mosaic?
How do I find out about other Internet resource discovery tools?
Table of Contents
1. Introduction................................................. 2
2. Acknowledgements............................................. 2
3. Questions About the Internet................................. 3
4. Questions About TCP/IP....................................... 5
5. Questions About the Domain Name System....................... 5
6. Questions About Internet Documentation....................... 6
7. Questions about Internet Organizations and Contacts.......... 13
8. Questions About Services..................................... 18
9. Mailing Lists and Sending Mail............................... 24
10. Miscellaneous "Internet lore" questions..................... 26
11. Suggested Reading........................................... 28
12. References.................................................. 29
13. Condensed Glossary.......................................... 31
14. Security Considerations..................................... 44
15. Authors' Addresses.......................................... 44
New users joining the Internet community have the same questions as
did everyone else who has ever joined. Our quest is to provide the
Internet community with up to date, basic Internet knowledge and
Future updates of this memo will be produced as User Services members
become aware of additional questions that should be included, and of
deficiencies or inaccuracies that should be amended in this document.
Although the RFC number of this document will change with each
update, it will always have the designation of FYI 4. An additional
FYI Q/A, FYI 7, is published that deals with intermediate and
advanced Q/A topics .
The following people deserve thanks for their help and contributions
to this FYI Q/A: Matti Aarnio (FUNET), Susan Calcari (InterNIC),
Corinne Carroll (BBN), Vint Cerf (MCI), Peter Deutsch (Bunyip), Alan
Emtage (Bunyip), John Klensin (UNU), Thomas Lenggenhager (Switch),
Doug Mildram (Xylogics), Tracy LaQuey Parker (Cisco), Craig Partridge
(BBN), Jon Postel (ISI), Matt Power (MIT), Karen Roubicek (BBN),
Patricia Smith (Merit), Gene Spafford (Purdue), and Carol Ward
(Sterling Software/NASA NAIC).
3. Questions About the Internet
3.1 What is the Internet?
The Internet is a collection of thousands of networks linked by a
common set of technical protocols which make it possible for users
of any one of the networks to communicate with or use the services
located on any of the other networks. These protocols are
referred to as TCP/IP or the TCP/IP protocol suite. The Internet
started with the ARPANET, but now includes such networks as the
National Science Foundation Network (NSFNET), the Australian
Academic and Research Network (AARNet), the NASA Science Internet
(NSI), the Swiss Academic and Research Network (SWITCH), and about
10,000 other large and small, commercial and research, networks.
There are other major wide area networks that are not based on the
TCP/IP protocols and are thus often not considered part of the
Internet. However, it is possible to communicate between them and
the Internet via electronic mail because of mail gateways that act
as "translators" between the different network protocols involved.
Note: You will often see "internet" with a small "i". This could
refer to any network built based on TCP/IP, or might refer to
networks using other protocol families that are composites built
of smaller networks.
See FYI 20 (RFC 1462), "FYI on 'What is the Internet?'" for a
lengthier description of the Internet .
3.2 I just got on the Internet. What can I do now?
You now have access to all the resources you are authorized to use
on your own Internet host, on any other Internet host on which you
have an account, and on any other Internet host that offers
publicly accessible information. The Internet gives you the
ability to move information between these hosts via file
transfers. Once you are logged into one host, you can use the
Internet to open a connection to another, login, and use its
services interactively (this is known as remote login or
"TELNETing"). In addition, you can send electronic mail to users
at any Internet site and to users on many non-Internet sites that
are accessible via electronic mail.
There are various other services you can use. For example, some
hosts provide access to specialized databases or to archives of
information. The Internet Resource Guide provides information
regarding some of these sites. The Internet Resource Guide lists
facilities on the Internet that are available to users. Such
facilities include supercomputer centers, library catalogs and
specialized data collections. The guide is maintained by the
Directory Services portion of the InterNIC and is available online
in a number of ways. It is available for anonymous FTP from the
host ds.internic.net in the resource-guide directory. It is also
readable via the InterNIC gopher (gopher internic.net). For more
information, contact email@example.com or call the InterNIC at
(800) 444-4345 or (908) 668-6587.
Today the trend for Internet information services is to strive to
present the users with a friendly interface to a variety of
services. The goal is to reduce the traditional needs for a user
to know the source host of a service and the different command
interfaces for different types of services. The Internet Gopher
(discussed more in the "Questions about Internet Services"
section) is one such service to which you have access when you
join the Internet.
3.3 How do I find out if a site has a computer on the Internet?
Frankly, it's almost impossible to find out if a site has a
computer on the Internet by querying some Internet service itself.
The most reliable way is to ask someone at the site you are
interested in contacting.
It is sometimes possible to find whether or not a site has been
assigned an IP network number, which is a prerequisite for
connecting an IP network to the Internet (which is only one type
of Internet access). To do so, query the WHOIS database,
maintained by the Registration Services portion of the InterNIC.
You have several options about how to do such a query. The most
common currently are to TELNET to the host rs.internic.net and
invoke one of the search interfaces provided, or to run a WHOIS
client locally on your machine and use it to make a query across
The RIPE Network Coordination Center (RIPE NCC) also maintains a
large database of sites to whom they have assigned IP network
numbers. You can query it by TELNETing to info.ripe.net and
stepping through the interactive interface they provide.
3.4 How do I get a list of all the hosts on the Internet?
You really don't want that. The list includes more than 1.5
million hosts. Almost all of them require that you have access
permission to actually use them. You may really want to know
which of these hosts provide services to the Internet community.
Investigate using some of the network resource discovery tools,
such as gopher, to gain easier access to Internet information.
4. Questions About TCP/IP
4.1 What is TCP/IP?
TCP/IP (Transmission Control Protocol/Internet Protocol) [4,5,6]
is the common name for a family of over 100 data-communications
protocols used to organize computers and data-communications
equipment into computer networks. TCP/IP was developed to
interconnect hosts on ARPANET, PRNET (packet radio), and SATNET
(packet satellite). All three of these networks have since been
retired; but TCP/IP lives on. It is currently used on a large
international network of networks called the Internet, whose
members include universities, other research institutions,
government facilities, and many corporations. TCP/IP is also
sometimes used for other networks, particularly local area
networks that tie together numerous different kinds of computers
or tie together engineering workstations.
4.2 What are the other well-known standard protocols in the TCP/IP
Other than TCP and IP, the three main protocols in the TCP/IP
suite are the Simple Mail Transfer Protocol (SMTP) , the File
Transfer Protocol (FTP) , and the TELNET Protocol . There
are many other protocols in use on the Internet. The Internet
Architecture Board (IAB) regularly publishes an RFC  that
describes the state of standardization of the various Internet
protocols. This document is the best guide to the current status
of Internet protocols and their recommended usage.
5. Questions About the Domain Name System
5.1 What is the Domain Name System?
The Domain Name System (DNS) is a hierarchical, distributed method
of organizing the name space of the Internet. The DNS
administratively groups hosts into a hierarchy of authority that
allows addressing and other information to be widely distributed
and maintained. A big advantage to the DNS is that using it
eliminates dependence on a centrally-maintained file that maps
host names to addresses.
5.2 What is a Fully Qualified Domain Name?
A Fully Qualified Domain Name (FQDN) is a domain name that
includes all higher level domains relevant to the entity named.
If you think of the DNS as a tree-structure with each node having
its own label, a Fully Qualified Domain Name for a specific node
would be its label followed by the labels of all the other nodes
between it and the root of the tree. For example, for a host, a
FQDN would include the string that identifies the particular host,
plus all domains of which the host is a part up to and including
the top-level domain (the root domain is always null). For
example, atlas.arc.nasa.gov is a Fully Qualified Domain Name for
the host at 220.127.116.11. In addition, arc.nasa.gov is the FQDN
for the Ames Research Center (ARC) domain under nasa.gov.
6. Questions About Internet Documentation
6.1 What is an RFC?
The Request for Comments documents (RFCs) are working notes of the
Internet research and development community. A document in this
series may be on essentially any topic related to computer
communication, and may be anything from a meeting report to the
specification of a standard. Submissions for Requests for
Comments may be sent to the RFC Editor (RFC-EDITOR@ISI.EDU). The
RFC Editor is Jon Postel.
Most RFCs are the descriptions of network protocols or services,
often giving detailed procedures and formats for their
implementation. Other RFCs report on the results of policy
studies or summarize the work of technical committees or
workshops. All RFCs are considered public domain unless
explicitly marked otherwise.
While RFCs are not refereed publications, they do receive
technical review from either the task forces, individual technical
experts, or the RFC Editor, as appropriate. Currently, most
standards are published as RFCs, but not all RFCs specify
Anyone can submit a document for publication as an RFC.
Submissions must be made via electronic mail to the RFC Editor.
Please consult RFC 1543, "Instructions to RFC Authors" , for
further information. RFCs are accessible online in public access
files, and a short message is sent to a notification distribution
list indicating the availability of the memo. Requests to be
added to this distribution list should be sent to RFC-
The online files are copied by interested people and printed or
displayed at their sites on their equipment. (An RFC may also be
returned via electronic mail in response to an electronic mail
query.) This means that the format of the online files must meet
the constraints of a wide variety of printing and display
Once a document is assigned an RFC number and published, that RFC
is never revised or re-issued with the same number. There is
never a question of having the most recent version of a particular
RFC. However, a protocol (such as File Transfer Protocol (FTP))
may be improved and re-documented many times in several different
RFCs. It is important to verify that you have the most recent RFC
on a particular protocol. The "Internet Official Protocol
Standards"  memo is the reference for determining the correct
RFC to refer to for the current specification of each protocol.
6.2 How do I obtain RFCs?
RFCs are available online at several repositories around the
world. For a list of repositories and instructions about how to
obtain RFCs from each of the major U.S. ones, send a message to
firstname.lastname@example.org. As the text of the message, type
"help: ways_to_get_rfcs" (without the quotes).
An example of obtaining RFCs online follows.
RFCs can be obtained via FTP from ds.internic.net with the
pathname rfc/rfcNNNN.txt (where "NNNN" refers to the number of the
RFC). Login using FTP, username "anonymous" and your email
address as password. The Directory Services portion of the
InterNIC also makes RFCs available via electronic mail, WAIS, and
To obtain RFCs via electronic mail, send a mail message to
email@example.com and include any of the following commands
in the message body:
document-by-name rfcnnnn where 'nnnn' is the RFC number
The text version is sent.
file /ftp/rfc/rfcnnnn.yyy where 'nnnn' is the RFC number.
and 'yyy' is 'txt' or 'ps'.
help to get information on how to use
6.3 How do I obtain a list of RFCs?
Several sites make an index of RFCs available. These sites are
indicated in the ways_to_get_rfcs file mentioned above and in the
6.4 What is the RFC-INFO service?
The Information Sciences Institute, University of Southern
California (ISI) has a service called RFC-INFO. Even though this
is a service, rather than a document, we'll discuss it in this
section because it is so closely tied to RFC information.
RFC-INFO is an email based service to help in locating and
retrieval of RFCs, FYIs, STDs, and IMRs. Users can ask for
"lists" of all RFCs and FYIs having certain attributes ("filters")
such as their ID, keywords, title, author, issuing organization,
and date. Once an RFC is uniquely identified (e.g., by its RFC
number) it may also be retrieved.
To use the service, send email to: RFC-INFO@ISI.EDU with your
requests as the text of the message. Feel free to put anything in
the SUBJECT, the system ignores it. All input is case
independent. Report problems to: RFC-MANAGER@ISI.EDU.
To get started, you may send a message to RFC-INFO@ISI.EDU with
requests such as in the following examples (without the
explanations between brackets):
Help: Help [to get this information]
List: FYI [list the FYI notes]
List: RFC [list RFCs with window as keyword or
List: FYI [list FYIs about windows]
List: * [list both RFCs and FYIs about windows]
List: RFC [list RFCs about ARPANET, ARPA NETWORK,
List: RFC [list RFCs issued by MITRE, dated
List: RFC [list RFCs obsoleting a given RFC]
List: RFC [list RFCs by authors starting with
Author: Bracken* [* is a wild card]
List: RFC [list RFCs by both Postel and Gillman]
Authors: J. Postel [note, the "filters" are ANDed]
Authors: R. Gillman
List: RFC [list RFCs by any Crocker]
List: RFC [list only RFCs by S.D. Crocker]
Authors: S.D. Crocker
List: RFC [list only RFCs by D. Crocker]
Authors: D. Crocker
Retrieve: RFC [retrieve RFC-822]
Doc-ID: RFC0822 [note, always 4 digits in RFC#]
Help: Manual [to retrieve the long user manual,
Help: List [how to use the LIST request]
Help: Retrieve [how to use the RETRIEVE request]
Help: Topics [list topics for which help is available]
Help: Dates ["Dates" is such a topic]
List: keywords [list the keywords in use]
List: organizations [list the organizations known to the
6.5 Which RFCs are Standards?
See "Internet Official Protocol Standards" (currently RFC 1540)
. This RFC documents the status of each RFC on the Internet
standards track, as well as the status of RFCs of other types. It
is updated periodically; make sure you are referring to the most
recent version. In addition, the RFC Index maintained at the
ds.internic.net repository notes the status of each RFC listed.
6.6 What is an FYI?
FYI stands for For Your Information. FYIs are a subset of the RFC
series of online documents.
FYI 1 states, "The FYI series of notes is designed to provide
Internet users with a central repository of information about any
topics which relate to the Internet. FYI topics may range from
historical memos on 'Why it was was done this way' to answers to
commonly asked operational questions. The FYIs are intended for a
wide audience. Some FYIs will cater to beginners, while others
will discuss more advanced topics."
In general, then, FYI documents tend to be more information
oriented, while RFCs are usually (but not always) more technically
FYI documents are assigned both an FYI number and an RFC number.
As RFCs, if an FYI is ever updated, it is issued again with a new
RFC number; however, its FYI number remains unchanged. This can
be a little confusing at first, but the aim is to help users
identify which FYIs are about which topics. For example, FYI 4
will always be FYI 4, even though it may be updated several times
and during that process receive different RFC numbers. Thus, you
need only to remember the FYI number to find the proper document.
Of course, remembering titles often works as well.
FYIs can be obtained in the same way RFCs can and from the same
repositories. In general, their pathnames are fyi/fyiNN.txt or
fyi/fyiNN.ps, where NN is the number of the FYI without leading
6.7 What is an STD?
The newest subseries of RFCs are the STDs (Standards). RFC 1311
, which introduces this subseries, states that the intent of
STDs is to identify clearly those RFCs that document Internet
standards. An STD number will be assigned only to those
specifications that have completed the full process of
standardization in the Internet. Existing Internet standards have
been assigned STD numbers; a list of them can be found both in RFC
1311 and in the, "Internet Official Protocol Standards" RFC.
Like FYIs, once a standard has been assigned an STD number, that
number will not change, even if the standard is reworked and re-
specified and later issued with a new RFC number.
It is important to differentiate between a "standard" and
"document". Different RFC documents will always have different
RFC numbers. However, sometimes the complete specification for a
standard will be contained in more than one RFC document. When
this happens, each of the RFC documents that is part of the
specification for that standard will carry the same STD number.
For example, the Domain Name System (DNS) is specified by the
combination of RFC 1034 and RFC 1035; therefore, both of those
RFCs are labeled STD 13.
6.8 What is the Internet Monthly Report?
The Internet Monthly Report (IMR) communicates online to the
Internet community the accomplishments, milestones reached, or
problems discovered by the participating organizations. Many
organizations involved in the Internet provide monthly updates of
their activities for inclusion in this report. The IMR is for
Internet information purposes only.
You can receive the report online by joining the mailing list that
distributes the report. Requests to be added or deleted from the
Internet Monthly Report list should be sent to "imr-
In addition, back issues of the Report are available for anonymous
FTP from the host ftp.isi.edu in the in-notes/imr directory, with
the file names in the form imryymm.txt, where yy is the last two
digits of the year and mm two digits for the month. For example,
the July 1992 Report is in the file imr9207.txt.
6.9 What is an Internet Draft? Are there any guidelines available
for writing one?
Internet Drafts (I-Ds) are the current working documents of the
IETF. Internet Drafts are generally in the format of an RFC with
some key differences:
- The Internet Drafts are not RFCs and are not a numbered
- The words INTERNET-DRAFT appear in place of RFC XXXX
in the upper left-hand corner.
- The document does not refer to itself as an RFC or as a
- An Internet Draft does not state nor imply that it is a
proposed standard. To do so conflicts with the role of
the IAB, the RFC Editor, and the Internet Engineering
Steering Group (IESG).
An Internet Drafts directory has been installed to make draft
documents available for review and comment by the IETF members.
These draft documents that will ultimately be submitted to the IAB
and the RFC Editor to be considered for publishing as RFCs. The
Internet Drafts Directories are maintained on several Internet
sites. There are several "shadow" machines which contain the IETF
and Internet Drafts Directories. They are:
West Coast (US) Address: ftp.isi.edu (18.104.22.168)
East Coast (US) Address: ds.internic.net (22.214.171.124)
Europe Address: nic.nordu.net (126.96.36.199)
Pacific Rim Address: munnari.oz.au (188.8.131.52)
To access these directories, use anonymous FTP. Login with
username "anonymous" and your email address as password (or
"guest" if that fails). Once logged in, change to the desired
directory with "cd internet-drafts". Internet Draft files can
then be retrieved. Once logged in, if you change to the directory
"ietf", you can retrieve a file called "1id-guidelines.txt", which
explains how to write and submit an Internet Draft.
6.10 How do I obtain OSI Standards documents?
OSI Standards documents are NOT available from the Internet via
anonymous FTP due to copyright restrictions. These are available
Omnicom Information Service
501 Church Street NE
Vienna, VA 22180 USA
Telephone: (800) 666-4266 or (703) 281-1135
Fax: (703) 281-1505
American National Standards Institute
11 West 42nd Street
New York, NY 10036 USA
Telephone: (212) 642-4900
However, the GOSIP specification which covers the use of OSI
protocols within the U.S. Government is available from the
National Institute of Standards and Technology (NIST). The final
text of GOSIP Version 2 is now available from both sites.
Available through anonymous FTP from osi.ncsl.nist.gov
./pub/gosip/gosip_v2.txt -- ascii
./pub/gosip/gosip_v2.txt.Z -- ascii compressed
./pub/gosip/gosip_v2.ps -- PostScript
./pub/gosip/gosip_v2.ps.Z -- PostScript compressed
Standards Processing Coordinator (ADP)
National Institute of Standards and Technology
Technology Building, Room B-64
Gaithersburg, MD 20899
7. Questions about Internet Organizations and Contacts
7.1 What is the IAB?
The Internet Architecture Board (IAB) is concerned with technical
and policy issues involving the evolution of the Internet
architecture . IAB members are deeply committed to making the
Internet function effectively and evolve to meet a large scale,
high speed future. The chairman serves a term of two years and is
elected by the members of the IAB. The IAB focuses on the TCP/IP
protocol suite, and extensions to the Internet system to support
multiple protocol suites.
The IAB performs the following functions:
1) Reviews Internet Standards,
2) Manages the RFC publication process,
3) Reviews the operation of the IETF and IRTF,
4) Performs strategic planning for the Internet, identifying
long-range problems and opportunities,
5) Acts as an international technical policy liaison and
representative for the Internet community, and
6) Resolves technical issues which cannot be treated within
the IETF or IRTF frameworks.
The IAB has two principal subsidiary task forces:
1) Internet Engineering Task Force (IETF)
2) Internet Research Task Force (IRTF)
Each of these Task Forces is led by a chairman and guided by a
Steering Group which reports to the IAB through its chairman. For
the most part, a collection of Research or Working Groups carries
out the work program of each Task Force.
All decisions of the IAB are made public. The principal vehicle
by which IAB decisions are propagated to the parties interested in
the Internet and its TCP/IP protocol suite is the Request for
Comments (RFC) note series and the Internet Monthly Report.
7.2 What is the IETF?
The Internet has grown to encompass a large number of widely
geographically dispersed networks in academic and research
communities. It now provides an infrastructure for a broad
community with various interests. Moreover, the family of
Internet protocols and system components has moved from
experimental to commercial development. To help coordinate the
operation, management and evolution of the Internet, the IAB
established the Internet Engineering Task Force (IETF).
The IETF is a large open community of network designers,
operators, vendors, and researchers concerned with the Internet
and the Internet protocol suite. The activity is performed in a
number of working groups organized around a set of several
technical areas, each working group has a chair, and each area is
managed by a technical area director. The IETF overall is managed
by its chair and the Internet Engineering Steering Group (IESG),
which is made up of the area directors.
The IAB has delegated to the IESG the general responsibility for
the resolution of short- and mid-range protocol and architectural
issues required to make the Internet function effectively, and the
development of Internet standards.
7.3 What is the IRTF?
To promote research in networking and the development of new
technology, the IAB established the Internet Research Task Force
(IRTF). The IRTF is a set of research groups, generally with an
Internet focus. The work of the IRTF is governed by its Internet
Research Steering Group (IRSG).
In the area of network protocols, the distinction between research
and engineering is not always clear, so there will sometimes be
overlap between activities of the IETF and the IRTF. There is, in
fact, considerable overlap in membership between the two groups.
This overlap is regarded as vital for cross-fertilization and
7.4 What is the Internet Society?
The Internet Society is a relatively new, professional, non-profit
organization with the general goal of fostering the well-being and
continued interest in, and evolution and use of the Internet. The
Society (often abbreviated ISOC) is integrating the IAB, IETF, and
IRTF functions into its operation.
The following goals of the Society are taken from its charter:
A. To facilitate and support the technical evolution of
the Internet as a research and education infrastructure,
and to stimulate the involvement of the scientific
community, industry, government and others in the
evolution of the Internet;
B. To educate the scientific community, industry and the
public at large concerning the technology, use and
application of the Internet;
C. To promote educational applications of Internet
technology for the benefit of government, colleges and
universities, industry, and the public at large;
D. To provide a forum for exploration of new Internet
applications, and to stimulate collaboration among
organizations in their operational use of the global
More information about the Internet Society is available for
anonymous FTP from the host: isoc.org in the directory: isoc.
Information is also available via the ISOC gopher, accessible via
"gopher isoc.org" if you are running a gopher client.
7.5 What is the IANA?
The task of coordinating the assignment of values to the
parameters of protocols is delegated by the Internet Architecture
Board (IAB) to the Internet Assigned Numbers Authority (IANA).
These protocol parameters include op-codes, type fields, terminal
types, system names, object identifiers, and so on. The "Assigned
Numbers" Request for Comments (RFC)  documents the currently
assigned values from several series of numbers used in network
protocol implementations. Internet addresses and Autonomous
System numbers are assigned by the Registration Services portion
of the InterNIC. The IANA is located at USC/Information Sciences
Current types of assignments listed in Assigned Numbers and
maintained by the IANA are:
Address Resolution Protocol Parameters
BOOTP Parameters and BOOTP Extension Codes
Domain System Parameters
Encoding Header Field Keywords
ESMTP Mail Keywords
Ethernet Multicast Addresses
Ethernet Numbers of Interest
Ethernet Vendor Address Components
IANA Ethernet Address Block
ICMP Type Numbers
IEEE 802 Numbers of Interest
Internet Protocol Numbers
Internet Version Numbers
IP Option Numbers
IP Time to Live Parameter
IP TOS Parameters
Internet Multicast Addresses
Inverse Address Resolution Protocol
Mail Encryption Types
Mail System Names
Mail Transmission Types
MILNET X.25 Address Mappings
MILNET Logical Addresses
MILNET Link Numbers
MIME/X.400 Mapping Tables
Network Management Parameters
Operating System Names
OSPF Authentication Codes
Point-to-Point Protocol Field Assignments
Protocol and Service Names
Protocol/Type Field Assignments
Public Data Network Numbers
Reverse Address Resolution Protocol Operation Codes
SUN RPC Numbers
TCP Option Numbers
TCP Alternate Checksum Numbers
Terminal Type Names
Well Known and Registered Port Numbers
X.25 Type Numbers
XNS Protocol Types
For more information on number assignments, contact: IANA@ISI.EDU.
7.6 What is a NIC? What is a NOC?
"NIC" stands for Network Information Center. It is an
organization which provides network users with information about
services provided by the network.
"NOC" stands for Network Operations Center. It is an organization
that is responsible for maintaining a network.
For many networks, especially smaller, local networks, the
functions of the NIC and NOC are combined. For larger networks,
such as mid-level and backbone networks, the NIC and NOC
organizations are separate, yet they do need to interact to fully
perform their functions.
7.7 What is the InterNIC?
The InterNIC is a five year project partially supported by the
National Science Foundation to provide network information
services to the networking community. The InterNIC began
operations in April of 1993 and is a collaborative project of
three organizations: General Atomics provides Information Services
from their location in San Diego, CA; AT&T provides Directory and
Database Services from South Plainsfield, NJ; and Network
Solutions, Inc. provides Registration Services from their
headquarters in Herndon, VA. Services are provided via the
network electronically, and by telephone, FAX, and hardcopy
General Atomics offers Information Services acting as the "NIC of
first and last resort" by providing a Reference Desk for new and
experienced users, and midlevel and campus NICs. The InterNIC
Reference Desk offers introductory materials and pointers to
network resources and tools.
AT&T services include the Directory of Directories, Directory
Services, and Database Services to store data available to all
Network Solutions, Inc. (NSI) provides Internet registration
services including IP address allocation, domain registration, and
Autonomous System Number assignment. NSI also tracks points of
contact for networks and domain servers and provides online and
telephone support for questions related to IP address or domain
All three portions of the InterNIC can be reached by calling (800)
444-4345 or by sending a message to firstname.lastname@example.org. Callers
from outside the U.S. can telephone +1 (619) 445-4600. Extensive
online information is available at host is.internic.net,
accessible via gopher or TELNET.
7.8 What is the DDN NIC (nic.ddn.mil)?
The DDN NIC is the Defense Data Network NIC. Until the formation
of the InterNIC, the DDN NIC had been responsible for many
services to the whole Internet, especially for registration
services. Now the DDN NIC focuses on serving its primary
constituency of MILNET users. Its host is nic.ddn.mil; the
address email@example.com may still be in older Internet
registration documentation. The DDN NIC maintains close ties to
the newer InterNIC.
7.9 What is the IR?
The Internet Registry (IR) is the organization that is responsible
for assigning identifiers, such as IP network numbers and
autonomous system numbers, to networks. The IR also gathers and
registers such assigned information. The IR delegates some number
assignment authority to regional registries (such as NCC@RIPE.NET
and APNIC-STAFF@APNIC.NET). However, it will continue to gather
data regarding such assignments. At present, the Registration
Services portion of the InterNIC at Network Solutions, Inc.,
serves as the IR.
8. Questions About Services
8.1 How do I find someone's electronic mail address?
There are a number of directories on the Internet; however, all of
them are far from complete. Many people can be found, however,
via the InterNIC WHOIS services, or KNOWBOT. Generally, it is
still necessary to ask the person for his or her email address.
8.2 How do I use the WHOIS program at the InterNIC Registration
There are several ways to search the WHOIS database. You can
TELNET to the InterNIC registration host, rs.internic.net. There
is no need to login. Type "whois" to call up the information
retrieval program, or choose one of the other options presented to
you. Help is available for each option. You can also run a
client of the WHOIS server and point it at any whois database
you'd like to search. Pointing a client at the whois server
ds.internic.net will enable you to query the databases at three
hosts: ds.internic.net, rs.internic.net, and nic.ddn.mil.
For more information, contact the InterNIC at (800) 444-4345 or
the registration services group at (703) 742-4777.
8.3 How do I use the Knowbot Information Service?
The Knowbot Information Service is a white pages "meta-service"
that provides a uniform interface to heterogeneous white pages
services in the Internet. Using the Knowbot Information Service,
you can form a single query that can search for white pages
information from the NIC WHOIS service, the PSI White Pages Pilot
Project, and MCI Mail, among others, and have the responses
displayed in a single, uniform format.
Currently, the Knowbot Information Service can be accessed through
TELNET to port 185 on hosts cnri.reston.va.us and
sol.bucknell.edu. From a UNIX host, use "telnet cnri.reston.va.us
185". There is also an electronic mail interface available by
sending mail to netaddress at either cnri.reston.va.us or
The commands "help" and "man" summarize the command interface.
Simply entering a user name at the prompt searches a default list
of Internet directory services for the requested information.
Organization and country information can be included through the
syntax: "firstname.lastname@example.org". For example, the queries
"droms@bucknell" and "email@example.com" are both valid. Note that
these are not Domain Names, but rather a syntax to specify an
organization and a country for the search.
8.4 What is the White Pages at PSI?
Performance Systems International, Inc. (PSI), sponsors a White
Pages Project that collects personnel information from member
organizations into a database and provides online access to that
data. This effort is based on the OSI X.500 Directory standard.
To access the data, TELNET to WP.PSI.COM and login as "fred" (no
password is necessary). You may now look up information on
participating organizations. The program provides help on usage.
For example, typing "help" will show you a list of commands,
"manual" will give detailed documentation, and "whois" will
provide information regarding how to find references to people.
For a list of the organizations that are participating in the
pilot project by providing information regarding their members,
type "whois -org *".
Access to the White Pages data is also possible via programs that
act as X.500 Directory User Agent (DUA) clients.
For more information, send a message to WP-INFO@PSI.COM.
8.5 What is USENET? What is Netnews?
USENET is the formal name, and Netnews a common informal name, for
a distributed computer information service that some hosts on the
Internet use. USENET handles only news and not mail. USENET uses
a variety of underlying networks for transport, including parts of
the Internet, BITNET, and others. Netnews can be a valuable tool
to economically transport traffic that would otherwise be sent via
mail. USENET has no central administration.
8.6 How do I get a Netnews feed?
To get a Netnews feed, you must acquire the server software, which
is available for some computers at no cost from some anonymous FTP
sites across the Internet, and you must find an existing USENET
site that is willing to support a connection to your computer. In
many cases, this "connection" merely represents additional traffic
over existing Internet access channels.
One well-known anonymous FTP archive site for software and
information regarding USENET is ftp.uu.net. There is a "news"
directory which contains many software distribution and
It is recommended that new users subscribe to and read
news.announce.newusers since it will help to become oriented to
USENET and the Internet.
8.7 What is a newsgroup?
A newsgroup is a bulletin board which readers interested in that
newsgroup's particular topic can read and respond to messages
posted by other readers. Generally, there will be a few "threads"
of discussion going on at the same time, but they all share some
common theme. There are approximately 900 newsgroups, and there
are more being added all the time.
There are two types of newsgroups: moderated and unmoderated. A
moderated newsgroup does not allow individuals to post directly to
the newsgroup. Rather, the postings go to the newsgroup's
moderator who determines whether or not to pass the posting to the
entire group. An unmoderated newsgroup allows a reader to post
directly to the other readers.
8.8 How do I subscribe to a newsgroup?
You don't subscribe to a newsgroup. Either you get it on your
machine or you don't. If there's one you want, all you can do is
ask the systems administrator to try to get it for you.
8.9 What is anonymous FTP?
Anonymous FTP is a conventional way of allowing you to sign on to
a computer on the Internet and copy specified public files from it
. Some sites offer anonymous FTP to distribute software and
various kinds of information. You use it like any FTP, but the
username is "anonymous". Many systems will request that the
password you choose is your email address. If this fails, the
generic password is usually "guest".
8.10 What is "archie"?
The archie system was created to automatically track anonymous FTP
archive sites, and this is still its primary function. The system
currently makes available the names and locations of some
2,100,000 files at some 1,000 archive sites.
Archie's User Access component allows you to search the "files"
database for these filenames. When matches are found, you are
presented with the appropriate archive site name, IP address, the
location within the archive, and other useful information.
You can also use archie to "browse" through a site's complete
listing in search of information of interest, or obtain a complete
list of the archive sites known to that server.
The archie server also offers a "package descriptions" (or
"whatis") database. This is a collection of names and
descriptions gathered from a variety of sources and can be used to
identify files located throughout the Internet, as well as other
useful information. Files identified in the whatis database can
then be found by searching the files database as described above.
8.11 How do I connect to archie?
You can connect to archie in a variety of ways. There is a
conventional TELNET interface, an electronic mail interface, and a
variety of client programs available. The use of a client is
strongly encouraged. There are currently 22 archie servers
located throughout the world.
To try the TELNET interface to archie you can TELNET to one of the
22 archie servers (preferably the one nearest you, and during
non-peak hours). Log in as "archie" (no password is required).
Type "help" to get you started.
Here is a list of archie servers as of the date this was written:
archie.au* 184.108.40.206 Australia
archie.edvz.uni-linz.ac.at* 220.127.116.11 Austria
archie.univie.ac.at* 18.104.22.168 Austria
archie.uqam.ca* 22.214.171.124 Canada
archie.funet.fi 126.96.36.199 Finland
archie.th-darmstadt.de* 188.8.131.52 Germany
archie.ac.il* 184.108.40.206 Israel
archie.unipi.it* 220.127.116.11 Italy
archie.wide.ad.jp 18.104.22.168 Japan
archie.hana.nm.kr* 22.214.171.124 Korea
archie.sogang.ac.kr* 126.96.36.199 Korea
archie.uninett.no* 188.8.131.52 Norway
archie.rediris.es* 184.108.40.206 Spain
archie.luth.se* 220.127.116.11 Sweden
archie.switch.ch* 18.104.22.168 Switzerland
archie.ncu.edu.tw* 22.214.171.124 Taiwan
archie.doc.ic.ac.uk* 126.96.36.199 United Kingdom
archie.unl.edu 188.8.131.52 USA (NE)
archie.internic.net* 184.108.40.206 USA (NJ)
archie.rutgers.edu* 220.127.116.11 USA (NJ)
archie.ans.net 18.104.22.168 USA (NY)
archie.sura.net* 22.214.171.124 USA (MD)
Note: Sites marked with an asterisk "*" run archie version 3.0.
You can obtain details on using the electronic mail interface by
sending mail to "archie" at any of the above server hosts. Put
the word "help" as the text of your message for directions.
Questions, comments, and suggestions can be sent to the archie
development group by sending mail to firstname.lastname@example.org.
8.12 What is "gopher"?
The Internet Gopher presents an extremely wide variety of diverse
types of information in an easy to use menu-driven interface.
Gopher servers link information from all around the Internet in a
manner that can be transparent to the user. (Users can easily
discover the source of any piece of information, however, if they
wish.) For example, gopher links databases of every type,
applications, white pages directories, sounds, and pictures.
Some gophers are available via TELNET. Since most gophers are
linked to other gophers, if you can get to one, you can get to
many. You can, for example, telnet to naic.nasa.gov and use their
The best way to use the gopher service, as with all client/server
type services, is by running your own gopher client. The Internet
Gopher was developed at the University of Minnesota. More
information is available for anonymous FTP on the host
8.13 What is the World Wide Web? What is Mosaic?
The World Wide Web is a distributed, hypermedia-based Internet
information browser. It presents users with a friendly point and
click interface to a wide variety of types of information (text,
graphics, sounds, movies, etc.) and Internet services. It is
possible to use the Web to access FTP archives, databases, and
even gopher servers.
The most familiar implementations of the World Wide Web are the
Mosaic clients developed by the National Center for Supercomputing
Applications (NCSA). Mosaic software is available online at
8.14 How do I find out about other Internet resource discovery
The field of Internet resource discovery tools is one of the most
dynamic on the Internet today. There are several tools in
addition to those discussed here that are useful for discovering
or searching Internet resources. The EARN (European Academic and
Research Network) Association has compiled an excellent document
that introduces many of these services and provides information
about how to find out more about them. To obtain the document,
send a message to email@example.com or
firstname.lastname@example.org. As the text of your
message, type "GET filename" where the filename is either
"nettools ps" or "nettols memo". The former is in PostScript
format. This document is also available for anonymous FTP on some
hosts, including naic.nasa.gov, where it is available in the
files/general_info directory as
earn-resource-tool-guide.ps and earn-resource-tool-guide.txt.
8.15 What is "TELNET"?
The term "TELNET" refers to the remote login that's possible on
the Internet because of the TELNET Protocol . The use of this
term as a verb, as in "telnet to a host" means to establish a
connection across the Internet from one host to another. Usually,
you must have an account on the remote host to be able to login to
it once you've made a connection. However, some hosts, such as
those offering white pages directories, provide public services
that do not require a personal account.
If your host supports TELNET, your command to connect to a remote
host would probably be "telnet <hostname>" or "telnet <host IP
address>". For example, "telnet rs.internic.net" or "telnet
9. Mailing Lists and Sending Mail
9.1 What is a mailing list?
A mailing list is an email address that stands for a group of
people rather than for an individual. Mailing lists are usually
created to discuss specific topics. Anybody interested in that
topic, may (usually) join that list. Some mailing lists have
membership restrictions, others have message content restrictions,
and still others are moderated. Most "public" mailing lists have
a second email address to handle administrative matters, such as
requests to be added to or deleted from the list. All
subscription requests should be sent to the administrative address
rather than to the list itself!
9.2 How do I contact the administrator of a mailing list rather
than posting to the entire list?
Today there are two main methods used by mailing list
adminstrators to handle requests to subscribe or unsubscribe from
their lists. The administrative address for many lists has the
same name as the list itself, but with "-request" appended to the
list name. So, to join the email@example.com list,
you would send a message to ietf-announce-
firstname.lastname@example.org. Most often, requests to a "-request"
mailbox are handled by a human and you can phrase your request as
a normal message.
More often today, especially for lists with many readers,
administrators prefer to have a program handle routine list
administration. Many lists are accessible via LISTSERVE programs
or other mailing list manager programs. If this is the case, the
administrative address will usually be something like
"email@example.com", where the address for the mailing list
itself will be "firstname.lastname@example.org". The same listserve address can
handle requests for all mailing lists at that host. When talking
with a program, your subscription request will often be in the
form, "subscribe ListName YourFirstName YourLastName" where you
substitute the name of the list for ListName and add your real
name at the end.
The important thing to remember is that all administrative
messages regarding using, joining, or quitting a list should be
sent to the administrative mailbox instead of to the whole
list so that the readers of the list don't have to read them.
9.3 How do I send mail to other networks?
Mail to the Internet is addressed in the form email@example.com.
Remember that a domain name can have several components and the
name of each host is a node on the domain tree. So, an example of
an Internet mail address is firstname.lastname@example.org.
There are several networks accessible via email from the Internet,
but many of these networks do not use the same addressing
conventions the Internet does. Often you must route mail to these
networks through specific gateways as well, thus further
complicating the address.
Here are a few conventions you can use for sending mail from the
Internet to three networks with which Internet users often
Internet user to Internet user:
Internet user to BITNET user:
Internet user to UUCP user:
Internet user to SprintMail user:
(Case is significant.)
Internet user to CompuServe user:
Replace the comma in the CompuServe userid (represented here
with x's) with a period, and add the compuserve.com domain
CompuServe user to Internet user:
Insert >internet: before an Internet address.
Internet user to MCIMail user:
10. Miscellaneous "Internet lore" questions
10.1 What does :-) mean?
In many electronic mail messages, it is sometimes useful to
indicate that part of a message is meant in jest. It is also
sometimes useful to communicate emotion which simple words do not
readily convey. To provide these nuances, a collection of "smiley
faces" has evolved. If you turn your head sideways to the left,
:-) appears as a smiling face. Some of the more common faces are:
:-) smile :-( frown
:) also a smile ;-) wink
:-D laughing 8-) wide-eyed
:-} grin :-X close mouthed
:-] smirk :-o oh, no!
10.2 What do "btw", "fyi", "imho", "wrt", and "rtfm" mean?
Often common expressions are abbreviated in informal network
postings. These abbreviations stand for "by the way", "for your
information", "in my humble [or honest] opinion", "with respect
to", and "read the f*ing manual" (with the "f" word varying
according to the vehemence of the reader :-).
10.3 What is the "FAQ" list?
This list provides answers to "Frequently Asked Questions" that
often appear on various USENET newsgroups. The list is posted
every four to six weeks to the news.announce.newusers group. It
is intended to provide a background for new users learning how to
use the news. As the FAQ list provide new users with the answers
to such questions, it helps keep the newsgroups themselves
comparatively free of repetition. Often specific newsgroups will
have and frequently post versions of a FAQ list that are specific
to their topics. The term FAQ has become generalized so that any
topic may have its FAQ even if it is not a newsgroup.
Here is information about obtaining the USENET FAQs, courtesy of
Many questions can be answered by consulting the most recent
postings in the news.announce.newusers and news.lists groups. If
those postings have expired from your site, or you do not get
news, you can get archived postings from the FTP server on the
These archived postings include all the Frequently Asked Questions
posted to the news.answers newsgroups, as well as the most recent
lists of Usenet newsgroups, Usenet-accessible mailing lists, group
moderators, and other Usenet-related information posted to the
news.announce.newusers and news.lists groups.
To get the material by FTP, log in using anonymous FTP (userid of
anonymous and your email address as password).
The archived files, and FAQ files from other newsgroups, are all
in the directory:
Archived files from news.announce.newusers and news.lists are in:
To get the information by mail, send an email message to: mail-
where TITLE is the archive title, and PART is the portion of the
posting you want.
Send a message containing "help" to get general information about
the mail server, including information on how to get a list of
archive titles to use in further send commands.
11. Suggested Reading
For further information about the Internet and its protocols in
general, you may choose to obtain copies of the following works as
well as some of the works listed as References:
Krol, Ed. (1992) The Whole Internet User's Guide and Catalog, 400
p. O'Reilly and Assoc., Inc. Sebastopol, CA.
Dern, Daniel P. (1993) The Internet Guide for New Users, 570 p.
McGraw-Hill, Inc. New York, NY.
Fisher, Sharon. (1993) Riding the Internet Highway, 266 p. New
Riders Publishing, Carmel, IN.
Frey, Donnalyn and Rick Adams. (1993) !%@:: A Directory of
Electronic Mail Addressing and Networks, (third edition) 443 p.
O'Reilly & Assoc., Inc. Sebastopol, CA.
Hoffman, Ellen and Lenore Jackson. (1993) "FYI on Introducing the
Internet: A Short Bibliography of Introductory Internetworking
Readings for the Network Novice," 4 p. (FYI 19/RFC 1463).
Kehoe, Brendan P. (1993) Zen and the Art of the Internet: A
Beginner's Guide, (second edition) 112 p. Prentice Hall, Englewood
LaQuey, Tracy with Jeanne C. Ryer. (1992) The Internet Companion:
A Beginner's Guide to Global Networking, 208 p. Addison-Wesley,
Malkin, Gary, S. and Tracy LaQuey Parker. (1993) "Internet Users'
Glossary," 53 p. (FYI 18/RFC 1392).
Marine, April, et al. (1993) Internet: Getting Started, 360 p.
Prentice Hall, Englewood Cliffs, NJ.
Martin, Jerry. (1993) "There's Gold in them thar Networks! or
Searching for Treasure in all the Wrong Places," 39 p. (FYI 10/RFC
Quarterman, John. (1993) "Recent Internet Books," 15 p. (RFC
 Reynolds, J., and J. Postel, "Assigned Numbers", STD 2, RFC 1340,
USC/Information Sciences Institute, July 1992.
 Postel, J., Editor, "Internet Official Protocol Standards", STD
1, RFC 1540, Internet Architecture Board, October 1993.
 Postel, J., and J. Reynolds, "File Transfer Protocol (FTP), STD
9, RFC 959, USC/Information Sciences Institute, October 1985.
 Postel, J., "Internet Protocol - DARPA Internet Program Protocol
Specification", STD 5, RFC 791, DARPA, September 1981.
 Postel, J., "Transmission Control Protocol - DARPA Internet
Program Protocol Specification", STD 7, RFC 793, DARPA, September
 Leiner, B., Cole, R., Postel, J., and D. Mills, "The DARPA
Internet Protocol Suite", IEEE INFOCOM85, Washington D.C., March
1985. Also in IEEE Communications Magazine, March 1985. Also as
 Cerf, V., "The Internet Activities Board" RFC 1160, CNRI, May
 Postel, J., "Simple Mail Transfer Protocol", STD 10, RFC 821,
USC/Information Sciences Institute, August 1982.
 Postel, J., and J. Reynolds, "TELNET Protocol Specification", STD
8, RFC 854, USC/Information Sciences Institute, May 1983.
 Postel, J., "Instructions to RFC Authors", RFC 1543,
USC/Information Sciences Institute, October 1993.
 Malkin, G., Marine, A., 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.
 Postel, J., "Introduction to the STD Notes", RFC 1311,
USC/Information Sciences Institute, March 1992.
 Krol, E., and E. Hoffman, "FYI on 'What is the Internet?'", FYI
20, RFC 1462, University of Illinois, Merit Network, Inc., May
13. Condensed Glossary
As with any profession, computers have a particular terminology all
their own. Below is a condensed glossary to assist in making some
sense of the Internet world.
ACM Association for Computing Machinery
A group established in 1947 to promote professional
development and research on computers.
address There are three types of addresses in common use within the
Internet. They are email address; IP, internet or Internet
address; and hardware or MAC address. An electronic mail
address is the string of characters that you must give an
electronic mail program to direct a message to a particular
person. A MAC address is the hardware address of a device
connected to a shared media. See "internet address" for its
AI Artificial Intelligence
The branch of computer science which deals with the
simulation of human intelligence by computer systems.
AIX Advanced Interactive Executive
IBM's version of Unix.
ANSI American National Standards Institute
This organization is responsible for approving U.S. standards
in many areas, including computers and communications.
Standards approved by this organization are often called ANSI
standards (e.g., ANSI C is the version of the C language
approved by ANSI). ANSI is a member of ISO. See also:
International Organization for Standardization.
ARP Address Resolution Protocol
Used to dynamically discover the low level physical network
hardware address that corresponds to the high level IP address
for a given host. ARP is limited to physical network systems
that support broadcast packets that can be heard by all hosts
on the network. It is defined in STD 37, RFC 826.
ARPA Advanced Research Projects Agency
An agency of the U.S. Department of Defense responsible for
the development of new technology for use by the military.
ARPA was responsible for funding much of the development of
the Internet we know today, including the Berkeley version of
Unix and TCP/IP.
ARPANET Advanced Research Projects Agency Network
A pioneering longhaul network funded by ARPA. It
served as the basis for early networking research as
well as a central backbone during the development of
the Internet. The ARPANET consisted of individual
packet switching computers interconnected by leased lines.
AS Autonomous System
A collection of routers under a single
administrative authority using a common Interior Gateway
Protocol for routing packets.
ASCII American (National) Standard Code for Information Interchange
A standard character-to-number encoding widely used in the
One character of information, usually eight bits wide.
b bit - binary digit
The smallest amount of information which may be stored
in a computer.
BBN Bolt Beranek and Newman, Inc.
The Cambridge, MA company responsible for development,
operation and monitoring of the ARPANET, and later,
the Internet core gateway system, the CSNET Coordination
and Information Center (CIC), and NSFNET Network
Service Center (NNSC).
BITNET An academic computer network that provides interactive
electronic mail and file transfer services, using a
store-and-forward protocol, based on IBM Network Job Entry
protocols. BITNET-II encapsulates the BITNET protocol within
IP packets and depends on the Internet to route them. There
are three main constituents of the network: BITNET in
the United States and Mexico, NETNORTH in Canada, and EARN in
Europe. There are also AsiaNet, in Japan, and connections in
South America. See CREN.
bps bits per second
A measure of data transmission speed.
BSD Berkeley Software Distribution
Implementation of the UNIX operating system and its utilities
developed and distributed by the University of California at
Berkeley. "BSD" is usually preceded by the version number of
the distribution, e.g., "4.3 BSD" is version 4.3 of the
Berkeley UNIX distribution. Many Internet hosts run BSD
software, and it is the ancestor of many commercial UNIX
catenet A network in which hosts are connected to networks
with varying characteristics, and the networks
are interconnected by gateways (routers). The
Internet is an example of a catenet.
CCITT International Telegraph and Telephone Consultative Committee
This organization is part of the United National International
Telecommunications Union (ITU) and is responsible for making
technical recommendations about telephone and data
Historically, one of a set of gateways (routers)
operated by the Internet Network Operations Center
at BBN. The core gateway system forms a central part
of Internet routing in that all groups had to advertise
paths to their networks from a core gateway.
CREN The Corporation for Research and Educational Networking
This organization was formed in October 1989, when BITNET and
CSNET (Computer + Science NETwork) were combined under one
administrative authority. CSNET is no longer operational, but
CREN still runs BITNET. See also: BITNET.
DARPA See ARPA.
A self-contained, independent entity of data carrying
sufficient information to be routed from the source
to the destination computer without reliance on earlier
exchanges between this source and destination computer and
the transporting network.
DCA Defense Communications Agency
Former name of the Defense Information Systems Agency
(DISA). See DISA.
DDN Defense Data Network
A global communications network serving the US Department of
Defense composed of MILNET, other portions of the Internet,
and classified networks which are not part of the Internet.
The DDN is used to connect military installations and is
managed by the Defense Information Systems Agency (DISA).
See also: DISA.
DDN NIC The Defense Data Network Network Information Center
The network information center at Network Solutions, Inc.,
funded by DISA, that provides information services to the
DDN community. It is also a primary repository for RFCs, and
a delegated registration authority for military networks.
DEC Digital Equipment Corporation
DECnet Digital Equipment Corporation network
A proprietary network protocol designed by Digital Equipment
Corporation. The functionality of each Phase of the
implementation, such as Phase IV and Phase V, is different.
A routing table entry which is used to direct packets
addressed to networks not explicitly listed in the routing table.
DISA Defense Information Systems Agency
Formerly called DCA, this is the government agency
responsible for installing the Defense Data Network
(DDN) portion of the Internet, including the MILNET
lines and nodes. Currently, DISA administers the
DDN, and supports the user assistance services of the
DNS The Domain Name System is a general purpose distributed,
replicated, data query service. The principal use is the
lookup of host IP addresses based on host names. The style of
host names now used in the Internet is called "domain name",
because they are the style of names used to look up anything
in the DNS. Some important domains are: .COM (commercial),
.EDU (educational), .NET (network operations), .GOV (U.S.
government), and .MIL (U.S. military). Most countries also
have a domain. For example, .US (United States), .UK (United
Kingdom), .AU (Australia). It is defined in STD 13, RFCs 1034
DOD U.S. Department of Defense
DOE U.S. Department of Energy
dot address (dotted address notation)
Dot address refers to the common notation for IP addresses of
the form A.B.C.D; where each letter represents, in decimal,
one byte of a four byte IP address.
Dynamic Adaptive Routing
Automatic rerouting of traffic based on a sensing and analysis
of current actual network conditions. NOTE: this does not
include cases of routing decisions taken on predefined
EARN European Academic Research Network
EBCDIC Extended Binary-coded Decimal Interchange Code
A standard character-to-number encoding used primarily by IBM
computer systems. See also: ASCII.
EGP Exterior Gateway Protocol
A protocol which distributes routing information to the
routers which connect autonomous systems. The term "gateway"
is historical, as "router" is currently the preferred term.
There is also a routing protocol called EGP defined in STD 18,
A 10-Mb/s standard for LANs, initially developed by Xerox,
and later refined by Digital, Intel and Xerox (DIX). All
hosts are connected to a coaxial cable where they contend for
network access using a Carrier Sense Multiple Access with
Collision Detection (CSMA/CD) paradigm.
FDDI Fiber Distributed Data Interface
A high-speed (100Mb/s) LAN standard. The underlying medium is
fiber optics, and the topology is a dual-attached,
counter-rotating token ring.
FIPS Federal Information Processing Standard
FTP File Transfer Protocol
A protocol which allows a user on one host to access, and
transfer files to and from, another host over a network.
Also, FTP is usually the name of the program the user invokes
to execute the protocol. It is defined in STD 9, RFC 959.
gateway See router.
A unit of data storage size which represents 10^9 (one
billion) characters of information.
10^9 bits of information (usually used to express a
data transfer rate; as in, 1 gigabit/second = 1Gbps).
GNU Gnu's Not UNIX
A UNIX-compatible operating system developed by the
Free Software Foundation.
header The portion of a packet, preceding the actual data, containing
source and destination addresses, and error checking and other
fields. A header is also the part of an electronic mail
message that precedes the body of a message and contains,
among other things, the message originator, date and time.
The part of an internet address that designates which
node on the (sub)network is being addressed.
IAB Internet Architecture Board
The technical body that oversees the development of the
Internet suite of protocols. It has two task forces: the IETF
and the IRTF.
IBM International Business Machines Corporation
ICMP Internet Control Message Protocol
ICMP is an extension to the Internet Protocol. It allows
for the generation of error messages,test packets and
informational messages related to IP. It is defined in STD 5,
IEEE Institute for Electrical and Electronics Engineers
IETF Internet Engineering Task Force
The IETF is a large open community of network designers,
operators, vendors, and researchers whose purpose is to
coordinate the operation, management and evolution of
the Internet, and to resolve short- and mid-range
protocol and architectural issues. It is a major source
of proposed protocol standards which are submitted to the
Internet Engineering Steering Group for final approval. The
IETF meets three times a year and extensive minutes of the
plenary proceedings are issued.
While an internet is a network, the term "internet" is usually
used to refer to a collection of networks interconnected with
The Internet (note the capital "I") is the largest internet in
the world. Is a three level hierarchy composed of backbone
networks (e.g., NSFNET, MILNET), mid-level networks, and stub
networks. The Internet is a multiprotocol internet.
The 32-bit address defined by the Internet Protocol
in STD 5, RFC 791. It is usually represented in dotted
decimal notation. An internet, or IP, address uniquely
identifies a node on an internet.
IP Internet Protocol
The Internet Protocol, defined in STD 5, RFC 791, is the
network layer for the TCP/IP Protocol Suite. It is a
connectionless, best-effort packet switching protocol.
IRTF Internet Research Task Force
The IRTF is chartered by the IAB to consider long-term
Internet issues from a theoretical point of view. It has
Research Groups, similar to IETF Working Groups, which are
each tasked to discuss different research topics. Multi-cast
audio/video conferencing and privacy enhanced mail are samples
of IRTF output.
ISO International Organization for Standardization
A voluntary, nontreaty organization founded in 1946 which is
responsible for creating international standards in many
areas, including computers and communications. Its members
are the national standards organizations of the 89 member
countries, including ANSI for the U.S.
A unit of data storage size which represents 10^3
(one thousand) characters of information.
10^3 bits of information (usually used to express a
data transfer rate; as in, 1 kilobit/second = 1Kbps = 1Kb).
LAN Local Area Network
A data network intended to serve an area of only a few square
kilometers or less. Because the network is known to cover
only a small area, optimizations can be made in the network
signal protocols that permit data rates up to 100Mb/s.
LISP List Processing Language
A high-level computer language invented by Professor John
McCarthy in 1961 to support research into computer based
logic, logical reasoning, and artificial intelligence. It
was the first symbolic (as opposed to numeric) computer
MAC Medium Access Control
The lower portion of the datalink layer. The MAC differs for
various physical media.
Mac Apple Macintosh computer.
MAN Metropolitan Area Network
A data network intended to serve an area approximating that of
a large city. Such networks are being implemented by
innovative techniques, such as running fiber cables through
subway tunnels. A popular example of a MAN is SMDS.
A unit of data storage size which represents
10^6 (one million) characters of information.
10^6 bits of information (usually used to express a
data transfer rate; as in, 1 megabit/second = 1Mbps).
MILNET Military Network
A network used for unclassified military production
applications. It is part of the DDN and the Internet.
MIT Massachusetts Institute of Technology
MTTF Mean Time to Failure
The average time between hardware breakdown or loss of
service. This may be an empirical measurement or a
calculation based on the MTTF of component parts.
MTTR Mean Time to Recovery (or Repair)
The average time it takes to restore service after a
breakdown or loss. This is usually an empirical measurement.
MVS Multiple Virtual Storage
An IBM operating system based on OS/1.
NASA National Aeronautics and Space Administration
NBS National Bureau of Standards
Now called NIST.
The network portion of an IP address. For a class A network,
the network address is the first byte of the IP address. For
a class B network, the network address is the first two bytes
of the IP address. For a class C network, the network address
is the first three bytes of the IP address. In each case, the
remainder is the host address. In the Internet, assigned
network addresses are globally unique.
NFS Network File System
A protocol developed by Sun Microsystems, and defined in RFC
1094, which allows a computer system to access files over a
network as if they were on its local disks. This protocol has
been incorporated in products by more than two hundred
companies, and is now a de facto Internet standard.
NIC Network Information Center
A organization that provides information, assistance and
services to network users.
NOC Network Operations Center
A location from which the operation of a network or internet
is monitored. Additionally, this center usually serves as a
clearinghouse for connectivity problems and efforts to resolve
NIST National Institute of Standards and Technology
United States governmental body that provides assistance in
developing standards. Formerly the National Bureau of
NSF National Science Foundation
A U.S. government agency whose purpose is to promote the
advancement of science. NSF funds science researchers,
scientific projects, and infrastructure to improve the quality
of scientific research. The NSFNET, funded by NSF, is an
essential part of academic and research communications.
NSFNET National Science Foundation Network
The NSFNET is a highspeed "network of networks" which is
hierarchical in nature. At the highest level is a
backbone network which spans the continental United
States. Attached to that are mid-level networks and
attached to the mid-levels are campus and local
networks. NSFNET also has connections out of the U.S.
to Canada, Mexico, Europe, and the Pacific Rim. The
NSFNET is part of the Internet.
NSFNET Mid-level Level Network
A network connected to the highest level of the NSFNET that
covers a region of the United States. It is to mid-level
networks that local sites connect. The mid-level networks
were once called "regionals".
OSI Open Systems Interconnection
A suite of protocols, designed by ISO committees, to be the
international standard computer network architecture.
OSI Reference Model
A seven-layer structure designed to describe computer network
architectures and the way that data passes through them. This
model was developed by the ISO in 1978 to clearly define the
interfaces in multivendor networks, and to provide users of
those networks with conceptual guidelines in the construction
of such networks.
OSPF Open Shortest-Path First Interior Gateway Protocol
A link state, as opposed to distance vector, routing protocol.
It is an Internet standard IGP defined in RFC 1247.
packet The unit of data sent across a network. "Packet" a generic
term used to describe unit of data at all levels of the
protocol stack, but it is most correctly used to describe
application data units.
PC Personal Computer
PCNFS Personal Computer Network File System
PPP Point-to-Point Protocol
The Point-to-Point Protocol, defined in RFC 1548, provides a
method for transmitting packets over serial point-to-point
A formal description of message formats and the rules
two computers must follow to exchange those messages.
Protocols can describe low-level details of
machine-to-machine interfaces (e.g., the order in
which bits and bytes are sent across a wire)
or high-level exchanges between allocation
programs (e.g., the way in which two programs
transfer a file across the Internet).
RFC The document series, begun in 1969, which describes the
Internet suite of protocols and related experiments. Not all
(in fact very few) RFCs describe Internet standards, but all
Internet standards are written up as RFCs.
RIP Routing Information Protocol
A distance vector, as opposed to link state, routing protocol.
It is an Internet standard IGP defined in STD 34, RFC 1058
(updated by RFC 1388).
RJE Remote Job Entry
The general protocol for submitting batch jobs and
retrieving the results.
router A device which forwards traffic between networks. The
forwarding decision is based on network layer information and
routing tables, often constructed by routing protocols.
RPC Remote Procedure Call
An easy and popular paradigm for implementing the
client-server model of distributed computing. In general, a
request is sent to a remote system to execute a designated
procedure, using arguments supplied, and the result returned
to the caller. There are many variations and subtleties in
various implementations, resulting in a variety of different
(incompatible) RPC protocols.
server A provider of resources (e.g., file servers and name servers).
SLIP Serial Line Internet Protocol
A protocol used to run IP over serial lines, such as telephone
circuits or RS-232 cables, interconnecting two systems. SLIP
is defined in STD 47, RFC 1055.
SMTP Simple Mail Transfer Protocol
A protocol, defined in STD 10, RFC 821, used to transfer
electronic mail between computers. It is a server to server
protocol, so other protocols are used to access the messages.
SNA Systems Network Architecture
A proprietary networking architecture used by IBM and
IBM-compatible mainframe computers.
SNMP Simple Network Management Protocol
The Internet standard protocol, defined in STD 15, RFC 1157,
developed to manage nodes on an IP network. It is currently
possible to manage wiring hubs, toasters, jukeboxes, etc.
subnet A portion of a network, which may be a physically independent
network, which shares a network address with other portions
of the network and is distinguished by a subnet number. A
subnet is to a network what a network is to an internet.
A part of the internet address which designates a subnet.
It is ignored for the purposes internet routing, but is
used for intranet routing.
T1 An AT&T term for a digital carrier facility used to transmit a
DS-1 formatted digital signal at 1.544 megabits per second.
T3 A term for a digital carrier facility used to transmit a DS-3
formatted digital signal at 44.746 megabits per second.
TCP Transmission Control Protocol
An Internet Standard transport layer protocol defined in STD
7, RFC 793. It is connection-oriented and stream-oriented, as
opposed to UDP.
TCP/IP Transmission Control Protocol/Internet Protocol
This is a common shorthand which refers to the suite
of application and transport protocols which run over IP.
These include FTP, TELNET, SMTP, and UDP (a transport
Telenet A public packet switched network using the CCITT X.25 protocols.
It should not be confused with Telnet.
TELNET Telnet is the Internet standard protocol for remote terminal
connection service. It is defined in STD 8, RFC 854 and
extended with options by many other RFCs.
A token ring is a type of LAN with nodes wired into a ring.
Each node constantly passes a control message (token) on to
the next; whichever node has the token can send a message.
Often, "Token Ring" is used to refer to the IEEE 802.5 token
ring standard, which is the most common type of token ring.
Tymnet A public character-switching/packet-switching network
operated by British Telecom.
UDP User Datagram Protocol
An Internet Standard transport layer protocol defined in STD
6, RFC 768. It is a connectionless protocol which adds a
level of multiplexing to IP.
ULTRIX UNIX-based operating system for Digital Equipment Corporation
UNIX An operating system developed by Bell Laboratories that
supports multiuser and multitasking operations.
UUCP UNIX-to-UNIX Copy Program
This was initially a program run under the UNIX operating
system that allowed one UNIX system to send files to another
UNIX system via dial-up phone lines. Today, the term is more
commonly used to describe the large international network
which uses the UUCP protocol to pass news and electronic mail.
VMS Virtual Memory System
A Digital Equipment Corporation operating system.
WAN Wide Area Network
A network, usually constructed with serial lines, which covers a
large geographic area.
WHOIS An Internet program which allows users to query databases of
people and other Internet entities, such as domains, networks,
and hosts. The information for people generally shows a
person's company name, address, phone number and email
XNS Xerox Network System
A network developed by Xerox corporation. Implementations
exist for both 4.3BSD derived systems, as well as the Xerox
X.25 A data communications interface specification developed to
describe how data passes into and out of public data
communications networks. The CCITT and ISO approved protocol
suite defines protocol layers 1 through 3.
14. Security Considerations
Security issues are not discussed in this memo.
15. Authors' Addresses
April N. Marine
Network Applications and Information Center
NASA Ames Research Center
Moffett Field, CA 94035-1000
Phone: (415) 604-0762
Joyce K. Reynolds
USC/Information Sciences Institute
4676 Admiralty Way, Suite 1001
Marina del Rey, CA 90292-6695
Phone: (310) 822-1511
Gary Scott Malkin
53 Third Avenue
Burlington, MA 01803
Phone: (617) 272-8140