Since many programs behave incorrectly when presented with illegal or invalid input, it may be possible for an attacker to "feed" a CGI script with input that will cause it to misbehave in such a way that the attacker can hack the site.

The work 'hacker' used to refer to know-it-all people who could figure out any electronic gizmo and then 'hack' it to perform some other, not necessarily illegal, task.

The purpose of this article is not to teach you how to hack sites successfully; I won't be teaching you how to steal credit card numbers, bring down Hotmail or reverse-engineer the latest release of Windows.

In a directed attack, a hacker who has entered your network might try to trawl through as much of it as possible,

Or, a hacker searching for insecure wireless connections can get into your systems from a car parked on the street.

A hacker can also steal sensitive information from your PC - like bank account details.

Attempting to gain entry to a system which you do not have an account on is called "Hacking" and is against the law.

Punch-card computer systems were soon the subject of hacking, and programmers delighted in finding ways of doing the same things with fewer punch cards.

Malicious hacking often takes primarily two things, time and software.

Once you become familiar with HTML and check the many online and hard copy references on the subject, you will learn to distinguish between "good" and "bad" HTML.

Although multifunction units have been around for several years and were slow to gain acceptance, their popularity has been growing, and by the year 2000 they are expected to represent about one in four sales of hard copy devices, according to Computer Intellience.

The printer takes the information on your screen and transfers it to paper or a hard copy.

Hard disk - This is large-capacity permanent storage used to hold information such as programs and documents.

This program systematically groups together the chunks of data that make up files and programs. Depending upon the size and state of your hard disk, the whole process may well take hours,

So your browser (Internet Explorer, Netscape, Opera, etc.) uses the hard disk to store HTML pages, putting them into a special folder on your disk.

Hardware options including scanners, fax machines, Internet/email connections, hard drives, CD-ROMs, and the list goes on and on.

There are two basic parts to a computer : Hardware and Software

All of the parts that comprise the computer system are collectively called “hardware”.

C uses pointers in three different ways : C uses pointers to create dynamic data structures : data structures built up from blocks of memory allocated from the heap at run-time.

Instead, certain areas of memory (Microsoft calls heaps) used by Windows have run low on space.

What is actually occurring when one 'defragments' the system memory is a dumping of main memory to the page file, forcing the computer to reload all of the active information into memory. In computing terms, this is called heap compaction, or Garbage Collection.

For more information on using these functions, we suggest you look them up in your windows manual or your windows help files.

All of these systems have a help section or FAQ clearly marked, so if you get into trouble, you can either hit your "back" button or try the site help file.

Any other C compiler you are using will normally come with a manual or a help file that contains a description of printf.

Hexadecimal (hex) is a base 16 way of representing one byte.

Hexadecimal digits use 16 values including 0 through 9, A, B, C, D, E, and F.

Hexadecimal (A Base 16 numbering system that has the "digits" 0123456789ABCDEF, you will notice that there are 16 different "digits" that's why it's a base 16 language)

To make a hidden folder viewable, perform the following steps:

open the Folder options diaog box as shown above, and change the hidden files and folders category to show hidden files and folders.

If your site uses multiple forms, in a shopping cart for example, it will probably rely upon hidden fields to transfer information from one page to the next (often referred to as persistence).

You may also hide the Taskbar if it interferes with some application at the bottom of the screen.

These buttons allow you to hide or show various icons and events on the display.

click plus to expand or show the sub-folders and minus to hide them Using Old DOS Programs

Unix variants operating systems would normally impose a hierarchical directory structure for the file system starting from root at the top and extending downward establishing major directories for /bin, /etc, /usr, /var, /home, etc.

Explorer users have it a little more difficult than Navigator users. Instead of seeing a simple hierarchical list of major newsgroups, they see the entire list in alphabetical order.

The most popular naming system is the Domain Name System (DNS), which is a collaborative, distributed, hierarchical system of managing namespaces where specific responsibilities for certain domains are delegated from root servers to subordinate servers.

When an item is selected (highlighted) a right mouse click will access a quick menu.

Highlight the name of the application/program that you want to remove and look for an Uninstall listing in the program folder and follow directions.

Highlight any service and right-click.

Does not specify the format or the size in megabytes of the hits it returns, nor does it tell you upfront exactly how many hits there are.

If the host is able to answer 20 requests per second, and the attacker is sending 50 per second, obviously the host will be unable to service all of the attacker's requests, much less any legitimate requests (hits on the web site running there, for example).

You may have a great site, but the fact is NO ONE CAN GUARANTEE how many hits you are going to get.

To send an attachment, compose the email and then, before sending it, hit the Attachment button in your mail program.

Basic hardware settings are configured using the BIOS setup program which may be accessed by hitting the DEL key while your computer is booting.

The next window just says that Windows is ready to start copying files. Hit next.

A discussion of viruses would not be complete without mentioning hoaxes. Malicious people without programming skills will send out fake virus warnings causing people to take unnessary measures which often cause your computer harm.

Typical hoaxes include a large percentage of computer viruses, chain letters, get rich quick schemes and appeals to send money. Some of these are jokes, but many are much more serious.

Remember, the items found in this section are HOAXES. None of this stuff is real so don't fall victim to it.

On one of the Ethernets, you might have hosts whose purpose is to service your organization's need for Internet connectivity. These will likely relay mail, news, and host DNS.

A "host" in the context of computers on the Internet is defined as any computer that has a live connection with the Internet.

Can a user's computer (i.e., a host) have connections to two different networks? A: Yes. Such computers are called *multihomed hosts*. Although such arrangements are possible, they are rare.

In this context it is said that the computer is "hosting" the web site.

The net effect of this action is that the remote computer hosting the Web page never comes into direct contact with anything on your home network, other than the proxy server.

It's important to remember that normally each Web site you host must have it's own static, public IP address.

The hub takes the signal from each computer and sends it to all of the other computers in your home.

With a hardware firewall, the firewall unit itself is normally the gateway. A good example is the Linksys Cable/DSL router. It has a built-in Ethernet card and hub.

To network your home server to other PCs you'll need a hub and one network card for each PC. You install a card in each PC, then attach each card to the hub using a cable.

HyperText is a document containing words that connect to other documents.

Hypertext - Any text that contains links to other documents, words or phrases in the document that can be chosen by a reader and which cause another document to be retrieved and displayed.

The term "hypertext" refers to the notion that one can click on a word or phrase displayed onscreen and a hotlink would cause it to jump to another text document, page, or section when selected.