Subject: FYI 7 draft

From: April Marine <[email-masked]>
Date: Sun, 8 Apr 2001 11:01:39 -0700 (PDT)

This is the draft Ray presented at the meeting.  I will also get it on the
web and send the URL, but didn't want to be the cause of EVEN FURTHER
delay while I did that.

FYI 7 not-yet-Internet-Draft
Ray Plzak
Minneapolis IETF
March 2001

Status of this Memo

This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026 [ ].

Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts. Internet-Drafts are draft documents valid for a maximum of
six months and may be updated, replaced, or obsoleted by other
documents at any time. It is inappropriate to use Internet- Drafts
as reference material or to cite them other than as "work in
progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.

1. Abstract

This memo provides information to the experienced Internet user
that wants to know more.  The term experienced user is used to
differentiate this user from the new users addressed by FYI4.  The
term experienced is relative. For the purpose of this memo
"experienced" is any user who is familiar with the concepts
described in FYI 4.  The information provided in this memo is what
may be described as an upper level or top level description of
some of the applications and protocols that are in common use on
the Internet today.  This memo does not provide precise technical
descriptions.  For these the reader is referred to the appropriate
RFC or other documentation.  A conscious effort has been made to
keep this memo brief but at the same time provide the depth of
information necessary to provide a general understanding of the
applications and protocols described.

2. Conventions used in this document

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
RFC-2119 [ ].

3. Doing Things on the Internet or "How Does It Work?"

3.1. How does email work?

Electronic mail is a lot like regular mail (also called snail
mail)  Your email message has a greeting to the addressee (or "to"
line), a subject, a body, a closing (or "from" line), enclosures
(also called attachments), carbon copies (cc), and blind carbon
copies (bcc). After you write your message, your email software
puts all this into an envelop with addressing information that
repeats some of these same elements on the envelop. It then looks
for a computer with a mail service called Simple Mail Transfer
Protocol (SMTP), which serves like a mail box outside your local
post office.  The SMTP service passes your message to nearby SMTP
computers (or servers) who know the destination computer (or
domain) for your addressee. If any of these SMTP servers have
trouble delivering your message, you will receive a delivery
notice explaining the nature of the problem. Because email can be
misunderstood or abused, users should be familiar with email
netiquette.  For more information see Netiquette Guidelines [FYI
28, RFC 1855].

3.2 What is a Mailing List?

A mailing list is a collection of email addresses of people
interested in a topic like hobbies, product updates, work
projects, and electronic newsletters.  Announcement lists go one
way from the owner to the members. Discussion lists are two-way.
Members send their messages to the list name at the mail list
server (e.g. [email-masked]), which in turn distributes
it to all members of a list. Messages sent to a moderated
discussion list are reviewed by the list owner before going out.
Messages to unmoderated discussion lists are not reviewed. You
subscribe and unsubscribe using a separate email address for list
maintenance, not the list address. Mail lists often have
descriptions and procedures you should review before joining.
Please stick to the list topic and use the list maintenance
address to leave the list.

3.3. How does the World Wide Web work?

Your web browser (Netscape, Internet Explorer, etc.) displays web
pages located on various computers operating web servers. These
web pages are written in Hypertext Markup Language (HTML) or
extensible Markup Language (XML).  The web server sends the web
pages and images to your PC using the Hypertext Transfer Protocol
(HTTP). Your web browser "renders" the page, placing images and
other page elements in their designated positions in the browser
window.  As you move your cursor across the page, you should
notice the cursor changes shape over what are called "hyperlinks."
Typically underlined and in blue, hyperlinks will take you to
other web pages, on the same server or on any web server in the
world. Pressing the hyperlink tells your browser to contact that
destination web server for the next web page.

3.4 What is Instant Messaging?

Many Internet service providers offer Instant messaging (IM) this
popular tool for friends to keep in touch using the Internet. You
announce your presence by entering your IM "handle" or nickname
into the IM pop-up window. You can use the same window to see your
friends are online. Unlike chat (see below), IM is one-to-one;
some chatters will have side conversations using IM. Many of the
current IM protocols are not yet standardized so you may not be
able to IM with someone on another service provider.

3.5 What is Chat and how does it work?

Chat is an electronic conversation between folks on the Internet.
Just as people congregate in small groups and discuss things,
chatters meet in chat rooms to discuss a topic. Chat rooms are
generally sponsored by an organization with an interest in the
topic area, like an online news organization holding a chat room
on current events.  To chat one person writes a message that is
read, as it is written, by the others who reply (or not) in turn.
First time chatters should be aware that there may be people in
the room who are just listening, just like a face to face party.
Also, just like at a party, some people may portray themselves to
be someone different than whom they really are.  Lastly, remember
that chatters come and go to chat rooms the same way people move
about at a party.

3.6 How does File transfer work?

Companies that distribute documents or software via the Internet
usually use the file transfer protocol (FTP) to send files to each
other or to you, the customer. FTP is designed to move large
amounts of data from one point to another without breaking the
file. FTP can be invoked in your browser by clicking on an FTP
link on a web page.

3.7 How do I send a lot of data across the Internet?

Although you can send files or documents as attachments using
email, most SMTP services limit the size or number of attachments.
You can use compression software to combine your documents into
one attachment and reduce the total size significantly. The free
software pkzip is readily available on web sites specializing in
internet utility software. If you routinely have to send a lot of
files or a number of large files, you may want to contact you
internet service provider to gain access to an HTTP or FTP server.
You can then send your addressees the location of the HTTP or FTP
server, and they can download these files using FTP instead of
clogging up email services with messages with large attachments.

3.8 How can I have fun on the Internet?

People on the Internet like to play games. These games can be role
playing games, action/adventure games, or online versions of old
standbys like chess.  Some games require the user to purchase and
install game software on their computer, while others are played
by going to a game site.  Just like other forms of game playing,
Internet game playing can be challenging, entertaining, and an
enjoyable social experience.  Don't be afraid to have fun.

4. Getting around the Internet

4.1.  What is an IP address?

An IP address is a 32-bit entity that uniquely identifies a node
on a network.  The original address came in three classes.  A
class "A" address, indicated by leading bits "01," identified one
of 2^24 nodes on one of 2^7 networks.  A class "B" network,
indicated by leading bits of "10," identified one of 2^16 nodes on
one of 2^16 networks.  A class C address, indicated by leading
bits "110," identified one of 2^8 nodes on one of 2^24 networks.
Later, the concept of subnets were added, wherein a 32-bit mask
was used to separate the node portion of the address from the
subnet portion.  This allowed an additional hierarchical level in
network addressing.  A multicast class was also added.  Indicated
by leading bits "1110," it identifies an address which is to be
received by multiple nodes.  More recently, Classless Inter-Domain
Routing (CIDR) is used.  It takes the 32-bit address and 32-bit
mask together to uniquely identify a network and node.  An IP
address is usually specified in dotted decimal notation.  That is,
each octet is specified as a decimal (as opposed to hex) and is
separated from the other octet by a decimal point.  For example,
128.202.1.47 would be 0x80ca012f in hex.  If that address had a
subnet mask of 255.255.255.0, the two would be specified as
128.202.1.47/24, indicating that there were 24 1-bits in the mask.
An Internet (capital "I") address is an IP address that uniquely
identifies a node on the global Internet.

4.2. What is a packet?

The word "packet" may be used to reference any unit on
transmittable information where the actual layer associated with
the packet is either implicit or unimportant.  A packet on the
wire is properly referred to as a frame.  A network layer (IP)
packet is called a datagram (the name was coined by Jon Postel).
A transport layer (TCP or UDP) packet is called a segment.  The
packet that the application hands to the network for transmission,
is called a packet.

4.3. What is a router?

A device which forwards traffic between (sub)networks based on
layer 3 (network layer) information.  The routing decision is
based on information maintained in routing tables, often
constructed by routing protocols.  Routers used to be referred to
as gateways, which is currently too generic a term.  Properly, a
router is a layer-3 gateway.  A bridge, by way of example, is a
layer-2 gateway.  Routing is the process of determining the
correct path for a packet.  Forwarding is the process by which a
packet is received on one interface and transmitted on another.

4.4. How are packets routed?

When a packet (more properly, a datagram) is received on a
router's interface, its IP header is examined.  If it fails any of
several validity checks, it is discarded and an ICMP error message
is (usually) sent to the originator of the datagram.  The
datagram's destination address is then examined.  If it specifies
one of the router's local addresses, or it is a broadcast, it is
delivered to the handler for the protocol specified in the header.
If it is a multicast, it may be delivered locally (if the router
is receiving that specific address).  It may also be forwarded
according to the set of rules or routing information governing
that multicast address.  If the datagram is for any other
destination, the best path to that destination (more specifically,
the next hop on the path) is determined and the packet is sent out
the interface that leads to that next hop.  The determination of
the best path (for unicast and multicast) datagrams is made based
on information in the router's routing tables.  That table is
populated by configured information (e.g., static routes), or
learned information from a routing protocol (e.g., RIP, OSPG, BGP-
4).  In most routers, routing information for unicast and
multicast routes are kept in separate tables and populated using
different routing protocols.  For unicast destinations, there are
several types of routes: host, subnet, network, supernet and
default.  Each type of route is less specific than the one before
it.  For example, a host route specifies one and only one host
(i.e., its subnet mask is 255.255.255.255), while a subnet route
points to all of the hosts on a specific subnet.  The default
route specifies the path for a datagram for which no other type of
route is available.  This hierarchy is referred to as longest
match because the preference is for routes which have longer
(i.e., more 1-bits) subnet masks, the default route having a mask
of 0.0.0.0.

4.5. How is a connection made between two computers on the Internet?

IP is a best-effort, datagram service.  This means that each
packet sent from one host to another is individually addressed and
independently routed.  For IP's point of view, there is no such
thing as a connection.  Applications that require reliable,
connection-oriented service (e.g., FTP, Telnet, HTTP) use a
transport layer protocol called TCP.  The establishment of a
"connection" between applications on two hosts has the follows the
following general pattern:

*The initiator enters a destination node name, which, using DNS,
is resolved into a destination Internet address.

*TCP uses a three-way handshake to establish a transport-layer
connection to the destination.  When the connection is open, TCP
signals the application, which either sends the first packet, or
establishes its own application-layer connection.

*Communication between the hosts continues until one side signals
its TCP to terminate the connection.  TCP then negotiates the
termination of the transport-layer connection, thus ending the
session.

4.6. What is DNS?

DNS is the Domain Name System.  It is a mechanism by which host
names can be converted (resolved) into Internet addresses.  A
Fully Qualified Domain Name (FQDN) has two parts: the hostname,
which is unique within the domain; and the domain name, which is
globally unique.  For example, atlas.supports.world.com has
"atlas" as a hostname and "supports.world.com" as a domain name.
The domain name is also made of multiple parts.  In this example,
"com" is the Top Level Domain (TLD), "world" is the domain
assigned out of com, and "supports" is a sub-domain chosen by the
owner of world.  There may be zero or more sub-domains.  The TLD
is the space from which the domain is assigned.  Contrary to
popular belief, there are more domains than com.  Originally,
"com" was used for vendors that created networking hardware and
software; today, it has become the catchall for domain trash.
Fortunately, the other domains (except, perhaps, "net" and "org")
have managed to retain their original intents.  "Net" is for
service provider  networks (e.g., ISPs).  "Org" is for non-profit
organizations.  The other TLDs have far more rigid controls.
"Edu" is for 4-year colleges (although some 2-year institutions
were grand fathered in).  "Mil" is the U.S. military, and "gov" is
the
U.S. government.  Two-letter TLDs are country codes (e.g., "us"
for the United States, "au" for Australia).  The sub-domains under
the country domains are managed by their respective countries.  In
the U.S., for example, there is one sub-domain for each state
(e.g., "ma.us" for Massachusetts, "ny.us" for New York).

4.7. How does DNS work?

The Domain Name System consists of a group of computers called
name servers.  These servers contain a special file called a zone
file that contains the information necessary to resolve the names
of the hosts in the domain into IP addresses or provide a
reference to the location of the zone file for a subdomain.
These servers are related to each other in the same hierarchical
manner as the domains they support.  Names are resolved to numbers
in the following manner:

The application that is requesting the resolution of a name to an
IP address contacts its local server.  If the local server knows
the answer it provides it to the requestor.  If it does not, it
must seek the answer elsewhere.

The search begins at the top of DNS tree, the root.  The local
server asks the root server for the answer.  The root server
provides a partial answer, in that it will identify the servers
for the TLD that contains the name.  The local server then asks
the TLD server for the answer.  The TLD server provides a partial
answer.  It identifies the servers for the subdomain of TLD that
contains the name.  The search continues in a similar manner until
the server that has the zone file that contains the entire name is
located.  This server then provides the IP number.

4.8. What is an intranet?

An intranet is a collection of networks that may or may not be
connected to the Internet.  Generally, an intranet is maintained
and administered by an organization that may be a commercial firm
or a government organization.  If the intranet is connected to the
Internet it is usually done at selected points that control access
from the intranet to the Internet and control access from the
Internet to the intranet.  Typically, only certain services such
as email are permitted to flow across these control points.

4.9. What is Tunneling?

Tunneling is the term applied to establishing an end-to-end
connection for the purpose of providing protected transfer of
information across the Internet.  One typical method of doing this
is encrypt packets at the transmission end and decrypt them at the
reception end.

5.  Security Considerations

5.1 How do I protect my personal information when I surf the
Internet?

The ubiquitous nature of the Internet has resulted in widespread
concern for the loss of personal privacy. Once your privacy is
compromised, you cannot get it back. The US Federal Trade
Commission http://WWW.FTC.GOV has established voluntary Fair
Information Practices covering notice, consent, access and
security.  The FTC surveyed over 300 web sites that collect
personal information and found that only 20 percent discussed all
four elements.  In a sample of more popular web sites, only 42
percent covered all four elements of privacy protection.  The FTC
found that the bankrupt eCommerce vendor Toysmart violated the FTC
Act by attempting to sell customer data after claiming that this
data would never be disclosed to a third party. Criminals can use
your personal data to steal your identity and credit rating.
California Public Interest Research Group found that victims spent
between two and four years removing an average of $18,000 in
fraudulent card charges charges.  Reputable sites should tell you
how they are protecting your information by adhering to the FTC's
recommended practices. If any of their statements make you
uncomfortable, leave the items blank or enter imaginary data. If
you do enter your data, print the notice for your files in case it
is violated.

5.2 What steps should I take to protect myself when shopping on the
Internet?

Know the vendor you are dealing with. Only enter credit card
information when suing a secure connection to the merchant; look
for the little padlock at the bottom of your web browser. US
citizens should use a credit card because US law limits your
liability for unauthorized charges to $50 dollars.  Debit cards do
not have such a limit. Use a credit card with a low credit limit.
Check your credit history periodically with credit bureaus;
thieves can open new accounts using your stolen personal data
unbeknownst to you. The US Federal Trade Commission
http://www.ftc.gov offers valuable additional suggestions for
online shoppers.

6. References

7. Acknowledgments

8. Author's Addresses

Full Copyright Statement

"Copyright (C) The Internet Society (date). All Rights Reserved.
This document and translations of it may be copied and furnished
to others, and derivative works that comment on or otherwise
explain it or assist in its implementation may be prepared,
copied, published and distributed, in whole or in part, without
restriction of any kind, provided that the above copyright notice
and this paragraph are included on all such copies and derivative
works. However, this document itself may not be modified in any
way, such as by removing the copyright notice or references to the
Internet Society or other Internet organizations, except as needed
for the purpose of developing Internet standards in which case the
procedures for copyrights defined in the Internet Standards
process must be followed, or as required to translate it into
languages other than English.

The limited permissions granted above are perpetual and will not
be revoked by the Internet Society or its successors or assigns.

This document and the information contained herein is provided on
an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

GLOSSARY
   Bradner, S., "The Internet Standards Process -- Revision 3",
BCP 9, RFC 2026, October 1996.

   Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997