Just Another networking faq -- 

A networking FAQ -

Version 1.2

The link to the author of this document.

ABSTRACT

HOW AM I DRIVING ?
This document is always in transition. If you notice that a frequently asked question is missing, please send it (and the answer!) to the editor at hermann@heimhardt.com. Suggestions for changes and comments are always welcome. Thanks to all the people who have contributed to this document!
Text in [square brackets] indicates unanswered questions and problems in this document. If you know the answer or have a comment send e-mail to the editor at the above stated address. Please help me out and send answers to some unanswered questions. The best answers are _brief_ ones followed by information on where to go for more detailed information.

TABLE OF CONTENTS

SECTION (0): THE BASICS

SECTION (1): WHAT IS... ?

SECTION (2): WHERE CAN I GET... ?

 

THE BASICS

What is this FAQ all about (Getting started) ?

Where can I get this FAQ ?

What is the most current version ?

Getting help when you have problems

What is this FAQ all about (Getting started) ?

This document is intended to cover the questions usually asked by novices. As a side-effect, it will help to the newsgroups from being cluttered by these questions. It helps users with questions by providing instant access to their answers; it helps other readers of the newsgroup, who will have to read fewer of the questions they see over and over again; it helps everyone by (hopefully) reducing traffic. This FAQ tries to clear up a few things about the Internet, and the trouble to connect to the Internet. Although the Intranet is not different from the Internet in terminology, some specialties are mentioned here.

This document should help you find answers to frequently asked questions. Usually, the answers are already available on the Net in one or more detailed documents. In these cases, this document will tell the reader where to find the information in question. Thus, when possible, this document will only point you to another document - that one may have the information you need, or it may point you somewhere else. (This may seem annoying at first, but offers multiple benefits. First, it reduces duplicated work. Second, it increases your chances of finding the most current, reliable information. Most importantly, it shows _how_ to find the information you need rather than simply giving you answers. "Teach a man to fish...")

This FAQ is purely a volunteer effort. Although every effort has been made to insure that answers are as accurate as possible, no guarantee is implied or intended. The editor and contributors have developed this FAQ as a service to the Internet. I hope you find it useful. If you find any errors please report them to hermann@heimhardt.com. Thank you.

Sorry folks, but this document will appear only in English. Maybe there are some volunteers that translate this to German. Please send your corrections, questions, and comments to the editor at hermann@heimhardt.com. Please indicate what version of this document you are referring to (diffs are highly appreciated).

Where can I get this FAQ ?

There is one way to get a copy of this FAQ.

Via WWW: http://heimhardt.com/htdocs/networkingfaq.html

What is the most current version ?

Version 1.1 (HTML)

History stack:

Version 1.1 (HTML)

  • reformatting and rewriting of parts
  • Intranet access cookbook included

Version 1.01 (HTML)

  • fixed error in cisco-networking-faq pointer.
  • created a history stack instead of a history list
  • changed some department informations
  • changed X.500 and DCE Answers

Version 1.0 (HTML)

  • created HTML document
  • error fixing
  • updates on various infos

Version 0.5 (Draft) ASCII groff source (never released)

  • added Section (1.17)

Version 0.4 (Draft) ASCII groff source

  • added Section (2.16)

Version 0.3 (Draft) ASCII groff source

  • corrected minor and major typos and groff formatting errors
  • added/changed dns subdomains
  • added info to SCN Section

Version 0.2 (Draft) ASCII groff source

  • corrected minor and major typos
  • corrected problems in formatting the document
  • added Nerv-Admins
  • created Postscript Version
  • new dns subdomains added

Version 0.1 (Draft) ASCII groff source

  • First ever release.

Getting help when you have problems

First of all: Read your manuals. If you are sure, that the problem has nothing to do with your local configuration consult your local network provider. They should know how to fix the problem.

SECTION 1: WHAT IS... ?

What is the Internet ?

What is DNS ?

What is a Name-Server ?

What is the World-Wide-Web (WWW) ?

What is NEWS ?

What is FTP ?

What is a router ?

What is routing ?

What is a default-route ?

What is a Firewall ?

What is SMTP ?

What is MIME ?

What is X.400 ?

What is X.500 ?

What is DCE ?

What is the Internet ?

Excerpt from: THE INTERNET COMPANION - A beginners guide to "Global Networking" by Tracy Laquey

  • The Internet is a loose amalgam of thousands of computer networks reaching millions of people all over the world. Although its original purpose was to provide researchers with access to expensive hardware resources, the Internet has demonstrated such speed and effectiveness as a communications medium that it has transcended the original mission. Today it's being used by all sorts of people -- educators, librarians, hobbyists, and businesspeople -- for a variety of purposes, from communicating with each other, to accessing valuable information and resources.
  • Excerpt from RFC1462: A commonly asked question is "What is the Internet ?" The reason such a question gets asked so often is because there's no agreed upon answer that neatly sums up the Internet. The Internet can be thought about in relation to its common protocols, as a physical collection of routers and circuits, as a set of shared resources, or even as an attitude about interconnecting and intercommunication. Some common definitions given in the past include:
  • a network of networks based on the TCP/IP protocols,
  • a community of people who use and develop those networks,
  • a collection of resources that can be reached from those networks.

Today's Internet is a global resource connecting millions of users that began as an experiment over 20 years ago by the U.S. Department of Defense. While the networks that make up the Internet are based on a standard set of protocols (a mutually agreed upon method of communication between parties), the Internet also has gateways to networks and services that are based on other protocols.

What is DNS ?

DNS stands for Domain Name Service. The purpose of domain names is to provide a mechanism for naming resources in such a way that the names are usable in different hosts, networks, protocol families, internist, and administrative organizations.

Name service is a network service providing name-to-address translation. Such service can be achieved in a number of ways. For a simple networking environment, it can be accomplished with a single central database containing name-to-address correspondence for all the pertinent network entities, such as hosts.

The name service at each domain is assumed to be provided by one or more name servers.

What is a Name-Server ?

A name server is a network service that enables clients to name resources or objects and share this information with other objects in the network. This in effect is a distributed data base system for objects in a computer network.

What is the World-Wide-Web (WWW) ?

The World-Wide-Web is a graphical Internet service with some very nice linking abilities. These features have made the Web the fastest growing Internet Service. The Web can link from any point in a document or image to any point in another document. However, you need a browser with a graphical user interface (GUI) like Netscape or Mosaic, or an ASCII browser like Lynx to take advantage from the Web. In fact you can access every Internet service (ftp, telnet, news, archie, ...) from the Web.

What is NEWS ?

Usenet is a worldwide network of computers that run, among other services, the News software. It is a public forum for the exchange of ideas in the form of articles that are broadcast to member sites. Net users can post articles, reply by mail or send follow-up articles to previous ones, or simply read the News using the netnews programs (nn, tin, trn, trumpet, ...). To bring structure in the collection of users and their ideas, news articles are classified into newsgroups.

What is FTP ?

FTP stands for file transfer protocol. FTP allows you to copy files from a remote computer to your local host and vice versa. FTP-Clients are available not only for UNIX Systems, but also for PCs, BS2000-Hosts, MVS-Hosts ...

What is a router ?

A router is a network "relay" that uses a protocol beyond the data-link protocol to route traffic between LANs and other network links. This approach creates two separate subnets and uses routing to filter the packets between them. Routers talk to each other using a routing protocol. The TCP/IP family of protocols has a bunch of routing protocols, such as RIP, EGP, BGP, OSPF, and dual IS-IS.

For further info please refer to the CISCO Networking FAQ

What is routing ?

Routing binds networks together. Without routing the network traffic would be limited to a single physical network. Routing allows traffic from your local network to reach its destination somewhere else in the world - perhaps after passing through many intermediate routers and networks. On a UNIX-Host you can show all routes using the netstat command:

root@hellraiser.rs.sni.de$ netstat -rn
Routing tables
Destination          Gateway              Flags    Refcnt Use        Interface
127.0.0.1            127.0.0.1            UH       1      0          lo0
default              149.202.66.1         UG       2      254210     et0
149.202              149.202.66.5         U        14     3495918    et0

The output of the netstat command shows that there are three routes defined: One route to the local host (127.0.0.1), one default route (default) and a route to the network 149.202.x.x (149.202). There are different Gateways to those networks. These gateways are routing IP packets to their destinations.

What is a default-route ?

A default route is used whenever there is no specific route to a destination, and it is often the only route you need. If your network has only one gateway, use a default route to direct all traffic bound for remote networks through that gateway.

What is a Firewall ?

A firewall computer provides strict access control between your systems inside the company and the outside world. A firewall system replaces an IP router with a multi-homed host that does not forward packets. Firewalls do sever the connection between networks. To provide the network behind the firewall with some level of network connectivity, the firewall performs certain unique functions. To minimize the inconvenience caused by a firewall, the system must do many more things, than a router does. The firewall must provide:

  • DNS for the outside world.
  • E-Mail forwarding
  • FTP service
  • Telnet service
  • WWW service

For further info please refer to The firewall FAQ

What is SMTP ?

SMTP stands for SIMPLE MAIL TRANSFER PROTOCOL.

Excerpt from RFC821:
The objective of Simple Mail Transfer Protocol (SMTP) is to transfer mail reliably and efficiently. SMTP is independent of the particular transmission subsystem and requires only a reliable ordered data stream channel. An important feature of SMTP is its capability to relay mail across transport service environments. A transport service provides an interprocess communication environment (IPCE). An IPCE may cover one network, several networks, or a subset of a network. It is important to realize that transport systems (or IPCEs) are not one-to-one with networks. A process can communicate directly with another process through any mutually known IPCE. Mail is an application or use of interprocess communication. Mail can be communicated between processes in different IPCEs by relaying through a process connected to two (or more) IPCEs. More specifically, mail can be relayed between hosts on different transport systems by a host on both transport systems.

For further info please refer to RFC821

What is MIME ?

MIME stands for Multipurpose Internet Mail Extensions.

Excerpt from RFC1521:
STD 11, RFC822 defines a message representation protocol which specifies considerable detail about message headers, but which leaves the message content, or message body, as flat ASCII text. This document redefines the format of message bodies to allow multi-part textual and non-textual message bodies to be represented and exchanged without loss of information. This is based on earlier work documented in RFC 934 and STD 11, RFC 1049, but extends and revises that work.

For further info please refer to RFC1521

What is X.400 ?

X.400 is the short name for the set of standards from ISO and the ITU that describe a mail service. It is the only non-proprietary standard for interchange of electronic mail that has the sanction of an official standards body. (ITU-TS, the International Telecommunications Union Telecommunication Standard Sector, was formerly named CCITT).

It currently exists in 3 flavors:

  • X.400/84: This is what most implementations today in fact run. It was documented in the "Red Book" series from ITU-TS.
  • ISO MOTIS/86 (mostly dead): This was the first attempt from ISO to agree to what ITU-TS had done. It died at the DIS stage. It contains some elements you need in order to conform to the European functional profiles and make manageable systems from the 1984 version, like domain-internal trace and the ISO6937 body part.
  • X.400/88: This is documented in the "Blue Book" series. Most people seem to think that this is a great improvement over 84, but the number of systems implementing it has been underwhelming. This one is also an International Standard by ISO.

What is X.500 ?

Excerpt from RFC1330:
X.500 is a CCITT/ISO standard which defines a global solution for the distribution and retrieval of information (directory service). The X.500 standard includes the following characteristics:

  • decentralized management,
  • powerful searching capabilities,
  • a single global namespace,
  • a structured framework for the storage of information.

The 1988 version of the X.500 standard specifies four models to define the Directory Service: the Information Model, the Functional Model, the Organizational Model and the Security Model. As is the nature of International standards work continues on the 1992 X.500 standard agreements.

For further info please refer to RFC1330

What is DCE ?

DCE (Distributed Computing Environment) is a future-oriented standard for distributed applications and is offered by the OSF (Open Systems Foundation).

Used in heterogeneous network environments (LAN or LAN segment coupled via WAN basing on IP using IPX25 or IP-ISDN) DCE offers a state-of-the-art of fast and distributed communication across a network. The remote procedure call of DCE (DCE RPC) makes the distribution of the applications a fast and secure way of computing. The thread architecture increases the performance within the client and server processes by parallelizing the working code.

A high standard of security for the applications (client and server) within the network is gained through DCE SECURITY, a sophisticated way of authenticating the user (Berbers) and authorizing his access to all objects that are to be protected. An additional data encryption makes communications even more secure against eavesdropping on the very hardware level.

The transparent access to all resources available on DCE hosts in the network is organized using the Cell Directory Service (CDS). Replication allows load balancing of the most important DCE servers (CDS and SEC) on multiple machines (you can have a read-only copy of the CDS name space or the security registry to fasten the access to the data or obtain higher security and avilability, e.g.).

Back to WHAT IS ... ? or Back to the TOC

SECTION 2: WHERE CAN I GET... ?

Where can I get pointers to other network resources ?

Where can I get RFCs ?

Where can I get FAQs ?

Where can I get additional information on the Internet ?

Where can I get additional information on Mail ?

Where can I get additional information on NEWS ?

Where can I get additional information on WWW ?

Where can I get additional information on FTP ?

Where can I get additional information on BIND ?

Where can I get additional information on "whatever" ?

Where can I get RFCs ?

Scan the FTP Servers:

Where can I get FAQs ?

Scan the FTP Servers:

Where can I get additional information on the Internet ?

There is so much information, I can't list all of it. However here are some hints for beginners:

Books:

Taken from Lehmanns WWW Bookstore

  • Kehoe, B.P.: Zen and the Art of the Internet. [Prentice Hall]
  • Bang, S. et al.: Internet Unleashed. [Sams]
  • Dern, D.P.: The Internet Guide for New Users. [McGraw-Hill]
  • Engst, A. et al.: Internet Starter Kit for Windows. [Hayden]
  • Estrada, S.: Connecting to the Internet. An O'Reilly Buyer's Guide. [O'Reilly]
  • Gilster, P.: Der Internet-Navigator. [Hanser]
  • Gilster, P.: The Internet Navigator. [Wiley]
  • Hahn, H., Stout, R.: The Internet Complete Reference. [McGraw-Hill]
  • Hahn, H., Stout, R.: The Internet Yellow Pages. [McGraw-Hill]
  • Hardie, E.T.L., Neou, V.: Internet: Mailing Lists. [Prentice Hall]
  • Krol, E.: Die Welt des Internet. [O'Reilly]
  • Krol, E.: The Whole Internet User's Guide and Catalogoue. [O'Reilly]
  • LaQuey, T.L.: The Internet Companion. [Addison-Wesley]
  • Scheller, M. u.a.: Internet: Werkzeuge und Dienste. [Springer]
  • Smith, R.: Navigating the Internet. [Sams]
  • Tollhurst, et al.: Using Internet. [Que]
  • Rose, M.T.: The Simple Book. [Prentice Hall]

Electronic books:

Where can I get additional information on mail ?

Read the RFCs and FAQs on the FTP-Servers. SMTP/Sendmail/X.400/MIME/...: A complete Index on all RFCs can be found on:

UseNet Discussions about mail:

Where can I get additional information on NEWS ?

Read the RFCs and FAQs on the FTP-Servers. A complete Index on all RFCs can be found on:

UseNet Discussions about news:

Where can I get additional information on WWW ?

Read the RFCs and FAQs on the FTP-Servers. A complete Index on all RFCs can be found on:

UseNet Discussions about WWW:

Where can I get additional information on FTP ?

Read the RFCs and FAQs on the FTP-Servers. A complete Index on all RFCs can be found on:

Where can I get additional information on BIND ?

Have a look at:

Where can I get additional information on "whatever" ?

Read the RFCs and FAQs on the FTP-Servers. A complete Index on all RFCs can be found on:

The author of this FAQ

Hermann Heimhardt  created the original version of this text and is currently regarded as the author.
Of course, it is virtually impossible to mention everybody who has contributed to this document ....
Nevertheless, a sincere "Thank you" goes to everbody who suggested positive changes, added frequent questions and their solutions, and helped us to improve this text. A lot of answers to questions has been taken from various RFCs and other FAQs. Thanks a lot to the authors of those documents.

Please help me make this document better by sending your comments to hermann@heimhardt.com.

Last update by Hermann Heimhardt on 1999-04-23 16:04:04
Back to the main page