i-Net
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INTERNET BASICS
1.1 Describe a URL, its functions and components, different types of
URLs, and the use of the appropriate type of URL to access a given type of
server. Content may include the following:
· Address Every
host must have a unique IP address. This address is a 32-bit binary number
written in decimal format as four octets (for example: 1.2.3.4). Because they
are just decimal representations of binary numbers, each octet must have a value
between 0 and 255. The first octet identifies the class of network, with the
following being valid entries:
1 126
|
Class A
|
128
191
|
Class B
|
192
223
|
Class C
|
224
239
|
Class D
(multicast)
|
Port TCP and UDP use port numbers for services. The port numbers for common
services are:
21
|
FTP
|
23
|
Telnet
|
25
|
SMTP
|
80
|
HTTP/WWW
|
110
|
POP3
|
119
|
NNTP
|
389
|
LDAP
|
These
ports are the default, and if you change the service to another port, those
accessing it must specify the new port in their request. For example, if the web
service is changed from port 80 to port 800, the URL to access the site
ds-technical.com becomes: http://www.ds-technical.com:800
1.2 Identify the issues that affect Internet site functionality (e.g.,
performance, security and reliability). Content may include the following:
· Internet
connection points the majority of users access the Internet through ISPs.
· Internet
Service Provider (ISP) ISPs access the Internet through Network Access
Points (NAPs).
· Corrupt
files corruption can occur at any time and prevent users from accessing your
resources successfully. It is important to test your files before
posting/uploading them, and to always continue to check them for corruption and
correct, as needed.
· Inability
to open files can be caused by browser dependencies. Try to avoid browser
dependencies whenever and wherever possible.
Resolution
of graphics is the number of determining factor in the clarity of the
graphics, and is expressed in bits: the greater the number of bits, the better
the graphic. While 24-bit graphics are perfect for an ideal world, if you want
to serve all users, you should use 8-bit graphics as that is as high as you can
go and support the 256-color monitors still in use.
1.3
Describe the concept of caching and its implications. Content may include the
following:
· Client
caching allows sites revisited to be brought to the browser quickly
· Cleaning
out client-side cache should be done on a routine basis such as with
Tweak/UI that can do so on each boot or activation and can restore hard
drive space
· Corrupt
files
·Searching
your site can be graphically represented via a site map.
· Indexing
your site for a search can be accomplished with an Index server. You can
exclude words from the search by creating a noise list.
INTERNET
CLIENTS
2.1
Describe the infrastructure needed to support an Internet client. Content could
include the following:
· Operating
system - The stack is implemented differently in different operating systems,
Windows-based operating systems implement it as a DLL - Winsock
· Web
browser uses port 80 by default, and can be configured with a number of
features (caching, cookie acceptance, etc.) . The most popular browsers, at this
time, are Netscape and Internet Explorer both of which run on multiple
operating system platforms.
· Hardware
platform (PC, WebTV, Internet phone) the one necessity is the TCP/IP
protocol.
2.2
Describe the use of Web browsers and various clients (e.g., FTP clients, Telnet
clients, email clients, all-in-one clients/universal clients) within a given
context of use. Examples of context could include the following:
· The
basic commands you would use (e.g., put and get) with each client (e.g., FTP,
Telnet) to place a single file on an FTP site, you use the put command.
To place multiple files on an FTP site, you can use mput. To
retrieve a single file from an FTP site, use get, or use mget
to retrieve multiple files. With telnet, the command to initiate the
session is telnet itself, the location to go to, for example:
Telnet
1.2.3.4
Or
Telnet redial.com
Once
a connection is established, you must logon to the server with a valid username
and password (plain text) as if you were sitting at the server. You can
end the connection a number of ways, with exit being the most
common command, then close the telnet application.
2.3
Explain the issues to consider when configuring the desktop. Content could
include the following:
· Host
file configuration the host file must exist on every machine that is
performing host name-to-IP address resolution in order for it to work properly.
It can consist of an unlimited number of lines, with each line limited to 255
characters in length. The format for the file is that the first column is an IP
address, and all other columns on that line (separated by any white space
tab, space, etc.) are aliases for that IP address. The pound sign (#) anywhere
on a line makes the rest of the line a comment.
· Configuring
browser (proxy configuration, client-side caching) proxy servers can be
configured to do active caching to automatically retrieve pages that are
commonly viewed and store them locally for access for users.
2.4
Describe MIME types and their components. Content could include the following:
· When
troubleshooting problems, look for revision dates, and manufacturer/vendor
values and use them to determine if you have the most current software
available. Troubleshooting problems and performance issues can often be tied to
compatibility issues and differing versions of the Web browser.
2.6
Explain the function of patches and updates to client software and associated
problems. Content could include the following:
Patches
should never be blindly applied as you run the risk of taking a working system
and making changes that can adversely affect performance. When new patches
become available, you should always download them and carefully read the
documentation, which accompanies them. If you are experiencing none of the
problems addressed by the patch, or there would be no performance gain by
applying it, then do not apply it. If the patch looks beneficial, then try it on
a single system first to look for problems that might arise before rolling it
out to all computers.
2.7
Describe the advantages and disadvantages of using a cookie and how to set
cookies. Content could include the following:
· API
The Application Programming Interfaces are the building blocks by which
Windows-based software applications are built by programmers.
· SQL
the Structured Query Language is used to find/place information in a
database. Using ODBC (Open DataBase Connectors), the Web server can interact
with a SQL server and pull up information such as from a catalog database and
post the results in HTML to the user.
·DLL
Dynamic Linking Libraries are the method by which common executable routines
are made available in the Windows-based environment. Drivers and executables
depend upon DLLs to provide functionality that can be accessed, making
programming much easier.
· Java
an object-oriented programming language created by Sun Microsystems that
allows programs to be run in almost every operating system (via a Java Virtual
Machine)
· Perl
Practical Extraction and Report Language an interpretive language
(requires an interpreter) that can be used to write CGI scripts and perform text
processing tasks
· C++
- the object-oriented counterpart to C. It is used for graphical environments
and runs on most operating systems.
· VBScript
a non-compiled scripting language based on Visual Basic that allows controls
to be added to web pages.
· XML
eXtensible Markup Language allows multiple HTML links (versus the
standard one) and is a chopped down version of SGML (Standard Generalized Markup
Language). It is useful for shopping sites and others that can have multiple
results needed for an action. Many believe XML will replace HTML eventually for
writing web pages.
· ASP
Active Server Pages run only on the Windows NT platform and allow processing
to be done on the server (which sends back pure HTML) and on the client (which
is processed within the browser, but can be viewed in Source.)
3.3
Describe the differences between a relational database and a non-relational
database.
A
flat-file database holds all data in one solitary table, while a relational
database stores data in different tables (each of which can be in a different
format). Relational databases are far more complicated than flat-file databases,
but also much more flexible and scalable for big installations.
3.4
Identify when to integrate a database with a Web site and the technologies used
to connect the two.
A
database should be integrated with a web site anytime you need to return values
from it to the user, or input values from the user into it. In the first
scenario, a database could be used to show inventory on hand when queried by
partners in your extranet. In the second scenario, a database could be
used to collect mailing addresses from users who want to receive your catalog.
ODBC - Open DataBase Connector allows the Web server to interact with a SQL
server.
3.5
Demonstrate the ability to create HTML pages.
Always
employ cross-browser coding in your html, and verify compatibility between
different browsers. Know that using the <UL> syntax will produce a
non-ordered, non-numbered list. Using the <OL> syntax will produce a
numbered and ordered list. To insert a command to run a script, use the syntax:
<script language="JavaScript">.
The correct syntax for a link to D S Technical Solutions is <A HREF="http://www.ds-technical.com">D
S Technical</A>. To insert an image, the correct syntax is <IMG SRC="image.gif
">
The "© " syntax produces the copyright symbol - ©. The <tr>
syntax is used to signify rows in a table and is not a required component on all
HTML pages.
3.6
Identify popular multimedia extensions or plug-ins. Examples could include the
following:
· Flash
from Macromedia, allows you to create vector-based web sites
· Real
Player plays RealAudio and RealVideo files on the Windows and Mac operating
systems
· Network
access points NAPs are how/where ISPs connect to the Internet and
effectively form the backbone.
· E-mail
· Website
4.3
Describe Internet domain names and DNS. Content could include the following:
· Hierarchical
structure DNS is organized in such a manner with the root of the naming tree
being . and everything funneling down from it, as in
bubba.ds-technical.com. which breaks out to:
.
|
the
root server
|
Com
|
commercial
venture
|
ds-technical
|
the
company
|
bubba
|
the computer in question
|
If
bubba is the primary server for the organization and running the web server,
then www.ds-technical.com becomes bubba.ds-technical.com.
·Top
level or original domains edu, com, mil, net, gov, and org exist within
the United States. Outside of the United States, two letter country level
domains are used, such as .UK, .au, etc.
4.4
Describe the nature, purpose, and operational essentials of TCP/IP. Content
could include the following:
·Public
versus private IP addresses when connecting to the Internet (meaning the
world), you must have a unique IP address for every single host within the
world. When you are not connecting to the world, however, then the addresses
must only be unique within your network. Public addressing requires the
uniqueness, while private addressing suggests that the following ranges be used:
Class of network desired
|
Starting address
|
Last available address
|
A
|
10.0.0.0
|
10.255.255.255
|
B
|
172.16.0.0
|
172.31.255.255
|
C
|
192.168.0.0
|
192.168.255.255
|
4.5
Describe the purpose of remote access protocols. Content could include the
following:
· PPP
Point to Point Protocol - an enhancement to SLIP, it offers error
correction, support for dynamic IP addressing, the use of protocols other than
TCP/IP and password logons
· POP3
used for retrieving mail
· HTTP
protocol of the web service
· NNTP
(news server) allows subscription to news servers
· LDAP
- Lightweight Directory Access Protocol - is built on the X.500 standard and
allows applications to obtain directory access and information.
· Telnet
allows establishment of a dumb terminal session
· Ping
an all-purpose utility for verifying that a remote host can be reached by
bouncing bytes of data to it
· ARP
Address Resolution Protocol shows the resolution between IP addresses
and physical (MAC) addresses
· Network
Analyzer used to analyze packets of data sent across the network
· Network
interface card (NIC) the physical entity within the host to which the
networking cabling is connected
· Modem
setup and commands most common commands are:
ATA
|
Answer
|
ATD
|
Dial
|
ATH
|
Hang
up
|
ATX
|
Exit
|
·
Bridge
used to connect two (and only two) networks together. Can be used with
nonroutable protocols
· Cache-in-a-box
available from a number of vendors, essentially a hard drive on the network
for storing cache
· Router
used to connect multiple networks together using routing tables requires
routable protocols
· Gateway
an upper layer device that can connect dissimilar networks together for the
purpose of passing application data (such as email) back and forth
· Firewall
either a hardware or software entity that protects a network by stopping
network traffic from passing through it. In most cases, a firewall is placed on
the network to allow all internal traffic to leave the network (emails to the
outside world, web access, etc.), but stop all traffic from the outside world
from entering the internal network
4.9
Describe various types of Internet bandwidth technologies (link types). Content
could include the following:
· T3/E3
A T3 is a dedicated line of 672 channels (E3 is the European counterpart)
able to run at speeds of 43Mbps
· X.25
a packet-switching standard widely used in WANs
· DSL
see section 4.8
4.10
Describe the purpose of various servers what they are, their functionality,
and features. Content could include the following:
· Mail
· Cache
- stores data
· Web
(HTTP) -
· Certificate
issues security keys
· E-commerce
allows for commercial transactions with security implied
Telnet
dumb terminal sessions
Auditing
Consists of:
·
intrusion
detection utilities
·
log files
·
auditing
logs
SET
(Secure Electronic Transactions) a standard for using digital signatures to
uniquely identify users and allow for credit card transactions over the Internet
5.2 Describe VPN and what it does.
· Denial of service (DoS) attacks wherein the system is kept so
busy responding to non-legitimate traffic/requests that it cannot service
legitimate users.
· Ping
floods - Flooding a site with ICMP echoes (also known as smurfing)
· User
names and passwords this is the minimal level of access that should be
acceptable.
· The
use of digital certificates
· Browser/client
· Intranet
with an Intranet, you isolate the site from the world (typically with a
firewall), and do everything you can to keep outsiders from knowing the site
exists or accessing it
· Internet
the purpose of an Internet site is for the world to know of its existence
and come to it to learn of your products, data, information, and other
offerings. By default, all users enter the site as the anonymous user and
permissions are assigned to anonymous to affect all users
BUSINESS
CONCEPTS
6.5 Define e-commerce terms and concepts. Content could
include the following:
· Business
to Business
· Internet
commerce
· Online
Cataloging
· Customer
self-service