Firewalls

GenXTechno Tags: firewall, proxy, server, filter

Internet firewalls are intended to keep the flames of Internet hell out of your private LAN. Or, to keep the members of your LAN pure and chaste by denying them access the all the evil Internet temptations.
The first computer firewall was a non routing UNIX host with connections to two different networks. One network card connected to the Internet and the other to the private LAN. To reach the Internet from the private network, you had to logon to the firewall (Unix) server. You then used the resources of the system to access the Internet. For example, you could use X−windows to run Netscape's browser on the firewall system and have the display on your work station. With the browser running on the firewall it has access to both networks.


Firewall Politics
You shouldn't believe a firewall machine is all you need. Set policies first. Firewalls are used for two purposes.
1. to keep people (worms / crackers) out.
2. to keep people (employees / children) in.

Create a security policy is simple.
1. describe what you need to service
2. describe the group of people you need to service
3. describe which service each group needs access to
4. for each service group describe how the service should be keep secure
5. write a statment making all other forms of access a vialation

Types of Firewalls

There are two types of firewalls.
1. Filtering Firewalls − that block selected network packets.
2. Proxy Servers (sometimes called firewalls) − that make network connections for you.

Packet Filtering Firewalls

Packet Filtering is the type of firewall built into the Linux kernel.
A filtering firewall works at the network level. Data is only allowed to leave the system if the firewall rules allow it. As packets arrive they are filtered by their type, source address, destination address, and port information contained in each packet.
Filtering firewalls do not provide for password controls. User can not identify themselves. The only identity a user has is the IP number assigned to their workstation. This can be a problem if you are going to use DHCP (Dynamic IP assignments). This is because rules are based on IP numbers you will have to adjust the rules as new IP numbers are assigned.

Proxy Servers

Proxies are mostly used to control, or monitor, outbound traffic. Some application proxies cache the
requested data. This lowers bandwidth requirements and decreases the access the same data for the next user. It also gives unquestionable evidence of what was transferred.
There are two types of proxy servers.
1. Application Proxies − that do the work for you.
2. SOCKS Proxies − that cross wire ports.

Application Proxy

The best example is a person telneting to another computer and then telneting from there to the outside world. With a application proxy server the process is automated. As you telnet to the outside world the client send you to the proxy first. The proxy then connects to the server you requested (the outside world) and returns the data to you.
Because proxy servers are handling all the communications, they can log everything they (you) do. For HTTP (web) proxies this includes very URL they you see. For FTP proxies this includes every file you download. They can even filter out "inappropriate" words from the sites you visit or scan for viruses.
Application proxy servers can authenticate users. Before a connection to the outside is made, the server can ask the user to login first. To a web user this would make every site look like it required a login.

SOCKS Proxy

A SOCKS server is a lot like an old switch board. It simply cross wires your connection through the system to another outside connection.
Most SOCKS server only work with TCP type connections. And like filtering firewalls they don't provide for user authentication. They can however record where each user connected to.

Digital Signature

GenXTechno Tags: digital, signature, certificate, crc

A digital signature is basically a way to ensure that an electronic document (e-mail, spreadsheet, text file, etc.) is authentic. Authentic means that you know who created the document and you know that it has not been altered in any way since that person created it.

There are several ways to authenticate a person or information on a computer:

• 
  
  Password - The use of a user name and password provide the most common form of authentication. You enter your name and password when prompted by the computer. It checks the pair against a secure file to confirm. If either the name or password do not match, then you are not allowed further access.
• 
  
  Checksum - Probably one of the oldest methods of ensuring that data is correct, checksums also provide a form of authentication since an invalid checksum suggests that the data has been compromised in some fashion. A checksum is determined in one of two ways. Let's say the checksum of a packet is 1 byte long, which means it can have a maximum value of 255. If the sum of the other bytes in the packet is 255 or less, then the checksum contains that exact value. However, if the sum of the other bytes is more than 255, then the checksum is the remainder of the total value after it has been divided by 256. Look at this example:

Byte 1	Byte 2	Byte 3	Byte 4	Byte 5	Byte 6	Byte 7	Byte 8	Total	Checksum
212	232	54	135	244	15	179	80	1151	127

1151 divided by 256 equals 4.496 (round to 4) Multiply 4 X 256 which equals 024 1151 minus 1024 equals 127

• 
  
  CRC (Cyclic Redundancy Check) - CRCs are similar in concept to checksums but they use polynomial division to determine the value of the CRC, which is usually 16 or 32 bits in length. The good thing about CRC is that it is very accurate. If a single bit is incorrect, the CRC value will not match up. Both checksum and CRC are good for preventing random errors in transmission, but provide little protection from an intentional attack on your data. The encryption techniques below are much more secure.
• 
  
  Private key encryption -Private key means that each computer has a secret key (code) that it can use to encrypt a packet of information before it is sent over the network to the other computer. Private key requires that you know which computers will talk to each other and install the key on each one. Private key encryption is essentially the same as a secret code that the two computers must each know in order to decode the information. The code would provide the key to decoding the message. Think of it like this. You create a coded message to send to a friend where each letter is substituted by the letter that is second from it. So "A" becomes "C" and "B" becomes "D". You have already told a trusted friend that the code is "Shift by 2". Your friend gets the message and decodes it. Anyone else who sees the message will only see nonsense.
• 
  
  Public key encryption - Public key encryption uses a combination of a private key and a public key. The private key is known only to your computer while the public key is given by your computer to any computer that wants to communicate securely with it. To decode an encrypted message, a computer must use the public key provided by the originating computer and it's own private key.

The key is based on a hash value. This is a value that is computed from a base input number using a hashing algorithm. The important thing about a hash value is that it is nearly impossible to derive the original input number without knowing the data used to create the hash value. Here's a simple example:

Input number	Hashing algorithm	Hash value
10667	Input # x 143	1525381

You can see how hard it would be to determine that the value of 1525381 came from the multiplication of 10667 and 143. But if you knew that the multiplier was 143, then it would be very easy to calculate the value of 10667. Public key encryption is much more complex than this example but that is the basic idea. Public keys generally use complex algorithms and very large hash values for encrypting: 40-bit or even 128-bit numbers. A 128-bit number has a possible 2¹²⁸ different combinations. That's as many combinations as there are water molecules in 2.7 million olympic size swimming pools. Even the tiniest water droplet you can image has billions and billions of water molecules in it!

• 
  
  Digital certificates - To implement public key encryption on a large scale, such as a secure Web server might need, requires a different approach. This is where digital certificates come in. A digital certificate is essentially a bit of information that says the Web server is trusted by an independent source known as a Certificate Authority. The Certificate Authority acts as the middleman that both computers trust. It confirms that each computer is in fact who they say they are and then provides the public keys of each computer to the other.

Encryption

GenXTechno Tags: asymmetric, symmetric, encryption, keys, public, private

Data encryption provides a way for you to protect your data from prying eyes. It also prevents unauthorized users from transmitting confidential data to the wrong party or performing any modifications to the data.
Data encryption works through a coding process to prevent documents, email messages, and other types of information from being accessed by unauthorized users. In an age of increased use of PC technology and sophisticated hackers, it is very easy for others to intercept your messages and read confidential documents.
“Encryption is the conversion of data into a form, called a ciphertext that cannot be easily understood by unauthorized people. Decryption is the process of converting encrypted data back into its original form, so it can be understood.”

Symmetric Encryption

Symmetric encryption involves transmission of a file through the program you are using. This type of encryption creates a key that jumbles up the file for emailing to the person on the receiving end. In order for the recipient to view the file, the sender must forward a separate decoding key which unscrambles the file so the recipient can view and read it.
The only problem with this type of data encryption is it is possible for someone to intercept the file as well as the decoding key during transmission.

Asymmetric Encryption

This type of data encryption is more secure than symmetric encryption because there are two keys involved with decoding the data, the public key and the private key. When the sender forwards a file, they do so by encrypting it with the recipient's public key. Once the recipient receives the file they access the data by using their private key. The process is much more secure but also takes longer to transmit.
Both types of encryption involve varied algorithms to produce the data depending on whether the encryption is symmetric or asymmetric. The process of the algorithm is used differently according to the type of encryption. This is why the person on the receiving end of the encrypted message must use the same process to access the data that was used to encrypt it.

Encryption Keys

Encryption keys have a wide variety of lengths and they also vary in strength. The possibility of number combinations is infinite, thus making it virtually impossible for even the most sophisticated hacker to guess the key combinations of the encryption.
Public asymmetric encryption schemes also use highly secure algorithms with a different method of encrypting and decrypting. This software utilizes two keys, known as a key pair. One encryption key is the public key, and can be freely shared or given to anyone because its only job is to encrypt. The other key is the private key, and is not shared. The private key is required to decrypt anything that has been encrypted by the public key.

WEB SERVERS

GenXTechno Tags: web, server, iis, pws, apache

A computer that runs a Web site. Using the HTTP protocol, the Web server delivers Web pages to browsers as well as other data files to Web-based applications. The Web server includes the hardware, operating system, Web server software, TCP/IP protocols and site content (Web pages, images and other files). If the Web server is used internally and is not exposed to the public, it is an "intranet server". Every Web server has an IP address and possibly a domain name.
Any computer can be turned into a Web server by installing server software and connecting the machine to the Internet. There are many Web server software applications, including public domain software from NCSA (National Center for Supercomputing Applications) and Apache, and commercial packages from Microsoft, Netscape and others.

Personal Web Server (PWS)

Personal Web Server is Microsoft's version of a Web server program for individual PC users who want to share Web pages and other files from their hard drive. PWS is a scaled-down version of Microsoft's more robust Web server, Internet Information Server IIS. PWS can be used with a full-time Internet connection to serve Web pages for a Web site with limited traffic. It can also be used for testing a Web site offline or from a "staging" site before putting it on a main Web site that is exposed to larger traffic.
PWS can be used together with Microsoft's FrontPage, a Web site design product, to upload Web pages from a remote location or to the local hard drive; to check for dead links; to create directories; and to set permissions. PWS is frequently used as part of the trend toward peer-to-peer exchange and publishing.
The equivalent program for the Macintosh is called Personal Web Sharing.

Internet Information Server

IIS (Internet Information Server) is a group of Internet servers (including a Web or Hypertext Transfer Protocol server and a File Transfer Protocol server) with additional capabilities for Microsoft's Windows NT and Windows 2000 Server operating systems. IIS is Microsoft's entry to compete in the Internet server market that is also addressed by Apache, Sun Microsystems, O'Reilly, and others. With IIS, Microsoft includes a set of programs for building and administering Web sites, a search engine, and support for writing Web-based applications that access databases. Microsoft points out that IIS is tightly integrated with the Windows NT and 2000 Servers in a number of ways, resulting in faster Web page serving.
A typical company that buys IIS can create pages for Web sites using Microsoft's Front Page product (with its WYSIWYG user interface). Web developers can use Microsoft's Active Server Page (ASP) technology, which means that applications - including ActiveX controls - can be imbedded in Web pages that modify the content sent back to users. Developers can also write programs that filter requests and get the correct Web pages for different users by using Microsoft's Internet Server Application Program Interface (ISAPI) interface. ASPs and ISAPI programs run more efficiently than common gateway interface (CGI) and server-side include (SSI) programs, two current technologies. (However, there are comparable interfaces on other platforms.)

Apache

Apache is generally recognized as the world's most popular Web server (HTTP server). Originally designed for Unix servers, the Apache Web server has been ported to Windows and other network operating systems (NOS). The name "Apache" derives from the word "patchy" that the Apache developers used to describe early versions of their software.

How to Setup Web Pages?

GenXTechno Tags: web, pages, page, setup, ftp

Set up your access to our FTP site - and FTP your web page to remote server.
Some important steps you have to follow for web page setup.

1. Planning your home page.
2. Getting everything you will need.
3. HTML Editors
4. FTP Clients
5. Create your home pages.
6. Uploading Web Pages.
7. Testing it out.

Planning Your Home Page

This is perhaps one of the most important steps in creating a home page because, either in your head or on paper, you are deciding what your page will look like and how you want to present it.

This can be as involved as drawing out a logical map of what connections you want, or as simple as sitting down and collecting your thoughts for what you want this page to be.

First, and foremost, consider what it is you want to put on your page. Common things to put on a page include:

• A list of links to the pages
• Information about your web site
• Information about the pages you have
• Other miscellaneous things

Getting Everything You Will Need.

The tools required to setup a home page are:

• Your Existing PPP Software
• An Editor of Your Choice (Text or HTML)
• An FTP Client

HTML Editors

You need to format your page using plain ASCII text. You create effects like bold, italics, and other effects like headings, etc, by using HTML tags. HTML stands for HyperText Markup Language.

FTP Clients

This is the software you will need to transport your web page(s) to Remote Site.

Create Your Home Page

Uploading Web Page(s)

This is the easy part and you're almost there.

1. Name your main page index.html.
2. Now you will want to switch to the FTP Client you had previously setup. You will now create a connection to client.visuallink.com with the following settings:
   
   • Hostname: 66.84.76.3 or www.xyz.com
   • Username: (Your username)
   • Password: (Your password)

Most of the recommended FTP clients work with the familiar drag-and-drop method of copying files. After bringing up your created home page on the 'local' side of the screen, you will simply 'drag' it over into your directory on the remote side.

• 
  
  Copy the files to your web directory. You must put them in your web directory on client.
• 
  
  Once your pages are uploaded to your home directory, you should (if you need to), rename the file with single extension .html.

Testing out Your Site

After successfully uploading your page, it will be located at the URL:

• http://www.xyz.com

TELNET & FTP

GenXTechno Tags: telnet, ftp, files, transfer, protocol

The Telnet protocol is often thought of as simply providing a facility for remote logins to computer via the Internet. This was its original purpose although it can be used for many other purposes. It is best understood in the context of a user with a simple terminal using the local telnet program (known as the client program) to run a login session on a remote computer where his communications needs are handled by a telnet server program. It should be emphasized that the telnet server can pass on the data it has received from the client to many other types of process including a remote login server. It is described in RFC854 and was first published in 1983.

Commands

The telnet protocol also specifies various commands that control the method and various details of the interaction between the client and server. These commands are incorporated within the data stream. The commands are distinguished by the use of various characters with the most significant bit set. Commands are always introduced by a character with the decimal code 255 known as an Interpret as command (IAC) character. The complete set of special characters is

Name	Decimal Code	Meaning
SE	240	End of subnegotiation parameters.
NOP	241	No operation
DM	242	Data mark. Indicates the position of a Synch event within the data stream. This should always be accompanied by a TCP urgent notification.
BRK	243	Break. Indicates that the "break" or "attention" key was hit.
IP	244	Suspend, interrupt or abort the process to which the NVT is connected.
AO	245	Abort output. Allows the current process to run to completion but do not send its output to the user.
AYT	246	Are you there. Send back to the NVT some visible evidence that the AYT was received.
EC	247	Erase character. The receiver should delete the last preceding undeleted character from the data stream.
EL	248	Erase line. Delete characters from the data stream back to but not including the previous CRLF.
GA	249	Go ahead. Used, under certain circumstances, to tell the other end that it can transmit.
SB	250	Subnegotiation of the indicated option follows.
WILL	251	Indicates the desire to begin performing, or confirmation that you are now performing, the indicated option.
WONT	252	Indicates the refusal to perform, or continue performing, the indicated option.
DO	253	Indicates the request that the other party perform, or confirmation that you are expecting the other party to perform, the indicated option.
DONT	254	Indicates the demand that the other party stop performing, or confirmation that you are no longer expecting the other party to perform, the indicated option.
IAC	255	Interpret as command

Associated with each of the these there are various possible responses

Sender Sent	Receiver Responds	Implication
WILL	DO	The sender would like to use a certain facility if the receiver can handle it. Option is now in effect
WILL	DONT	Receiver says it cannot support the option. Option is not in effect.
DO	WILL	The sender says it can handle traffic from the sender if the sender wishes to use a certain option. Option is now in effect.
DO	WONT	Receiver says it cannot support the option. Option is not in effect.
WONT	DONT	Option disabled. DONT is only valid response.
DONT	WONT	Option disabled. WONT is only valid response.

For example if the sender wants the other end to suppress go-ahead it would send the byte sequence 255(IAC), 251(WILL), 3The final byte of the three byte sequence identifies the required action. For some of the negotiable options values need to be communicated once support of the option has been agreed. This is done using

The Telnet Protocol
Telnet Negotiable Options Many of those listed are self-evident, but some call for more comments.

• Suppress Go Ahead

The original telnet implementation defaulted to "half duplex" operation. This means that data traffic could only go in one direction at a time and specific action is required to indicate the end of traffic in one direction and that traffic may now start in the other direction. [This similar to the use of "roger" and "over" by amateur and CB radio operators.] The specific action is the inclusion of a GA character in the data stream.Modern links normally allow bi-directional operation and the "suppress go ahead" option is enabled.

• Echo

The echo option is enabled, usually by the server, to indicate that the server will echo every character it receives. A combination of "suppress go ahead" and "echo" is called character at a time mode meaning that each character is separately transmitted and echoed. There is an understanding known as kludge line mode which means that if either "suppress go ahead" or "echo" is enabled but not both then telnet operates in line at a time mode meaning that complete lines are assembled at each end and transmitted in one "go".

• Linemode

This option replaces and supersedes the line mode kludge.

• remote flow control

This option controls where the special flow control effects of Ctrl-S/Ctrl-Q are implemented. Telnet control functions The telnet protocol includes a number of control functions. These are initiated in response to conditions detected by the client (usually certain special keys or key combinations) or server. The detected condition causes a special character to be incorporated in the data stream.

• Interrupt Process

This is used by the client to cause the suspension or termination of the server process. Typically the user types Ctrl-C on the keyboard. An IP (244) character is included in the data stream.

• Abort Output

This is used to suppress the transmission of remote process output. An AO (238) character is included in the data stream.

• Are You There

This is used to trigger a visible response from the other end to confirm the operation of the link and the remote process. An AYT (246) character is incorporated in the data stream.

• Erase character

Sent to the display to tell it to delete the immediately preceding character from the display. An EC (247) character is incorporated in the data stream.

• Erase line

Causes the deletion of the current line of input. An EL (248) character is incorporated in the data stream.

• Data Mark

Some control functions such as AO and IP require immediate action and this may cause difficulties if data is held in buffers awaiting input requests from a (possibly misbehaving) remote process. To overcome this problem a DM (242) character is sent in a TCP Urgent segment, this tells the receiver to examine the data stream for "interesting" characters such as IP, AO and AYT. This is known as the telnet synch mechanism.A DM not in a TCP Urgent segment has no effect.

The telnet command
On most Unix systems a telnet session can be initiated using the telnet command. telnet <remote host> but if the user just types telnet then various options and subcommands are available which can be used to study the behavior of the session.
Here's an exmaple of a telnet session from scitsc to ccub
bash$ telnet
telnet> toggle options
Will show option processing.
telnet> open ccub
Trying 63.14.239.165 ...
Connected to laynetworks.com.
Escape character is '^]'.
SENT do SUPPRESS GO AHEAD
SENT will TERMINAL TYPE (reply)
RCVD do TERMINAL TYPE (don't reply)
RCVD will SUPPRESS GO AHEAD (don't reply)
RCVD will ECHO (reply)
SENT do ECHO (reply)
RCVD do ECHO (reply)
SENT wont ECHO (reply)
UNIX(r) System V Release 4.0 (ccub)
RCVD dont ECHO (don't reply)
login: Login timed out after 60 seconds
Connection closed by foreign host.

Search Engines

GenXTechno Tags: search, engines, crawler, spider

What is a search engine?

A search engine is a coordinated set of programmes that includes:

• A spider (also called a "crawler" or a "bot") that goes to every page or representative pages on every Web site that wants to be searchable and reads it, using hypertext links on each page to discover and read a site's other pages
• A program that creates a huge index (sometimes called a "catalogue") from the pages that have been read
• A program that receives your search request, compares it to the entries in the index, and returns results to you

An alternative to using a search engine is to explore a structured directory of topics. Yahoo, which also lets you use its search engine, is the most widely-used directory on the Web. A number of Web portal sites offer both the search engine and directory approaches to finding information.

Crawler-based search engines

Crawler-based search engines, such as Google, create their listings automatically. They "crawl" or "spider" the web, then people search through what they have found.
If you change your web pages, crawler-based search engines eventually find these changes, and that can affect how you are listed. Page titles, body copy and other elements all play a role.
Crawler-based search engines have three major elements. First is the spider, also called the crawler. The spider visits a web page, reads it, and then follows links to other pages within the site. This is what it means when someone refers to a site being "spidered" or "crawled." The spider returns to the site on a regular basis, such as every month or two, to look for changes.
Everything the spider finds goes into the second part of the search engine, the index. The index, sometimes called the catalogue, is like a giant book containing a copy of every web page that the spider finds. If a web page changes, then this book is updated with new information.
Sometimes it can take a while for new pages or changes that the spider finds to be added to the index. Thus, a web page may have been "spidered" but not yet "indexed." Until it is indexed -- added to the index -- it is not available to those searching with the search engine.

Human-powered directories

A human-powered directory, such as the Open Directory, depends on humans for its listings. You submit a short description to the directory for your entire site, or editors write one for sites they review. A search looks for matches only in the descriptions submitted.

"Hybrid search engines" or mixed results

In the web's early days, it used to be that a search engine either presented crawler-based results or human-powered listings. Today, it extremely common for both types of results to be presented. Usually, a hybrid search engine will favour one type of listings over another. For example, MSN Search is more likely to present human-powered listings from LookSmart. However, it does also present crawler-based results (as provided by Inktomi), especially for more obscure queries.

Different search engine approaches

• Major search engines index the content of a large portion of the web and provide results that can run for pages - and consequently overwhelm the user.
• Specialized content search engines are selective about what part of the web is crawled and indexed. They provide provide a shorter but more focused list of results.
• Ask Jeeves provides a general search of the web but allows you to enter a search request in natural language, such as "What's the weather in Seattle today?"
• Special tools and some major websites such as Yahoo let you use a number of search engines at the same time and compile results for you in a single list.

How Search Engines Work

The term "search engine" is often used generically to describe both crawler-based search engines and human-powered directories. These two types of search engines gather their listings in radically different ways.

Crawler-Based Search Engines

Crawler-based search engines, such as Google, create their listings automatically. They "crawl" or "spider" the web, then people search through what they have found.
If you change your web pages, crawler-based search engines eventually find these changes, and that can affect how you are listed. Page titles, body copy and other elements all play a role.

Human-Powered Directories

A human-powered directory, such as the Open Directory, depends on humans for its listings. You submit a short description to the directory for your entire site, or editors write one for sites they review. A search looks for matches only in the descriptions submitted.
Changing your web pages has no effect on your listing. Things that are useful for improving a listing with a search engine have nothing to do with improving a listing in a directory. The only exception is that a good site, with good content, might be more likely to get reviewed for free than a poor site.

"Hybrid Search Engines" Or Mixed Results

In the web's early days, it used to be that a search engine either presented crawler-based results or human-powered listings. Today, it extremely common for both types of results to be presented. Usually, a hybrid search engine will favor one type of listings over another. For example, MSN Search is more likely to present human-powered listings from LookSmart. However, it does also present crawler-based results (as provided by Inktomi), especially for more obscure queries.

The Parts Of A Crawler-Based Search Engine

Crawler-based search engines have three major elements. First is the spider, also called the crawler. The spider visits a web page, reads it, and then follows links to other pages within the site. This is what it means when someone refers to a site being "spidered" or "crawled." The spider returns to the site on a regular basis, such as every month or two, to look for changes.
Everything the spider finds goes into the second part of the search engine, the index. The index, sometimes called the catalog, is like a giant book containing a copy of every web page that the spider finds. If a web page changes, then this book is updated with new information.
Sometimes it can take a while for new pages or changes that the spider finds to be added to the index. Thus, a web page may have been "spidered" but not yet "indexed." Until it is indexed -- added to the index -- it is not available to those searching with the search engine.
Search engine software is the third part of a search engine. This is the program that sifts through the millions of pages recorded in the index to find matches to a search and rank them in order of what it believes is most relevant. You can learn more about how search engine software ranks web pages on the aptly-named How Search Engines Rank Web Pages page.

Search Engine Placement Tips

· Pick Your Target Keywords
· Position Your Keywords
Make sure your target keywords appear in the crucial locations on your web pages. The page's HTML title tag is most important. Failure to put target keywords in the title tag is the main reason why perfectly relevant web pages may be poorly ranked. More about the title tag can be found on the How To Use HTML Meta Tags page.
· Create Relevant Content
Changing your page titles is not necessarily going to help your page do well for your target keywords if the page has nothing to do with the topic. Your keywords need to be reflected in the page content.
· Avoid Search Engine Stumbling Blocks
Some search engines see the web the way someone using a very old browser might. They may not read image maps. They may not read frames. You need to anticipate these problems, or a search engine may not index any or all of your web pages.
· Frames Can Kill
Some of the major search engines cannot follow frame links. Make sure there is an alternative method for them to enter and index your site, either through meta tags or smart design.

COMMUNICATION SOFTWARES & INTERNET TOOLS

GenXTechno Tags: communication, software, page, gate, spy, mail, text, aloud, wireless, ftp, client

Communication software is used to provide remote access to systems and exchange files and messages in text, audio and/or video formats between different computers or user IDs. This includes terminal emulators, file transfer programs, chat and instant messaging programs, as well as similar functionality integrated within MUDs (multi-user dungeonN).
Email Software - all types for email software
Advanced Email Verifier - Keep your mailing lists and address books clean with this powerful tool that eliminates non-working email addresses reliably.
Advanced Email Parser - software allows to create the incoming email processing system automaticaly.
G-Lock Easy Mail – it is a bulk email software that can be used for email marketing. Messages are sent directly from your PC to the recipient's mail server (without using any ISP's SMTP server).
PageGate - messaging server software sends email messages or email notification to pagers and cell phones.
SpyMail - messaging server software sends email messages or email notification to pagers and cell phones.
Poco Mail - a specific focus: to allow you to take full potential of e-mail, whether you get one or one hundred messages a day
I am a Big Brother - monitor your children's instant messages, emails, web surfing and much more while undetected by the user.
Text Aloud - converts any text into spoken words. Instead of the valuable time you spend reading on your email it is read to you!
KeyLog Pro - Secretly record chats, emails, instant messages, keystrokes, Hotmail, AOL emails, Yahoo! chat and AOL chat
Wireless Software - all types of wireless related software.
PageGate - network paging gateway that allows text messages to be sent to cell phones, pagers and PIMs from any combination of six different interfaces (e-mail, web, GUI, TAP-in, Serial and commandline).
NotePager Pro - send text or SMS messages to pagers, mobile phones, and PIMs using an easy to use desktop application.
NotePager Net - full feature network paging software that allows for all users on a network to share a commmon modem, phone line and database to facilitate the sending of text messages to pagers, cellular phones or other messaging devices.
Broadcast Software - including MP3s, audio recording and call recording software
Telephony Software - IVR and telephony related applications
Call Corder - records telephone conversations directly to your hard disk with a single push of button, optionally playing a legal disclaimer before recording. It stores calls as standard Windows sound files, adding a memo to allow fast and easy call navigation.
Modem Spy - handy utility for recording phone conversations. It can playback recorded messages via modem or via sound card. There is an option to record all incoming and outgoing calls. You will need voice modem in order to run program.
Extra Dialer Pro - extra Dialer is a unique program that uses advanced technology for voice messages broadcasting. It provides the most cost effective and efficient technology solution for performing important yet sometimes repetitive, as well as time and cost consuming tasks.
Advanced Call Center - easy-to-use answering machine software for your voice modem. All necessary functions are supported: Caller ID lets you see and hear who's calling via screen pop-ups, distinctive rings and caller's name announcement with speech synthesis.
Active Phone Server -an application designed to manage your incoming and outgoing phone calls. All essential features are supported: advanced answering machine, caller ID function which displays a caller's information when a call is received, and enables you to customize voices and melodies for each phone number.
PhoneWorks - an easy-to-use and powerful telephone, voice mail answering system, and fax messaging solution for your PC. PhoneWorks solves your messaging problems by dramatically simplifying how you read, listen to, and manage your daily information.
Internet Communication Software - all types of internet communication software
Instant Communication Software - including web based instant messaging, and peer to peer messaging.
Voicemail Software - voicemail software solutions and recording
Messaging Software - all types of messaging and related programs
Mass Communication - tools and utilities for mass communication
Paging Software - software for paging
SMS Communication Software - SMS messaging related software

INTERNET TOOLS

• Browser/Server security information - for reading all header and Javascript information available from web page or your browser
• Web Content analysis - complex analysis of a web page content. Highly recommened for web developers!
• Web Traffc analysis - tons of information about site popularity on the Internet (historical traffic, ranking, page views and more). Highly recommened for web marketing!
• Geographical IP Lookup - it shows ability to find geographical location based on IP address. It displays interactive map with address information.

Tools

Applications, clients and servers; enable storage of information on servers for access by users who have client software for a range of purposes more complex than just utility tasks

• Serverwatch: Information about Internet servers; includes news, downloads, and reviews of Web, mail, news, ftp, and other servers; part of internet.com
• FTP RFC: File Transfer Protocol (FTP); describes FTP terms and operation; Request for Comments 959, J. Reynolds, J. Reynolds, October 1985
• FTPplanet: Directory of File Transfer Protocol information and software; includes instruction guides, help, and technical information about using FTP
• FTP Clients: File Transfer Protocol software; description and reviews of downloadable software for transferring files over the Internet; from internet.com portal
• Telnet RFC: The Remote User Telnet Service; describes the telnet protocol and its operation; Request for Comments 818, J. Postel, November 1982
• Telnet Clients: Telnet software; description and reviews of downloadable software for allowing you to login to a remote computer host and use it as if on a terminal; from internet.com portal
• WWW: World Wide Web Consortium; develops interoperable technologies (specifications, guidelines, software, and tools) for the World Wide Web
• WWW Browsers: Web Browsers; a list of downloads for Web browser software with reviews; from internet.com portal
• Web reference: Web technician's reference; includes discussion of technical issues involved in Web implementation
• Web Development: Web content development; discussion of a methodology for Web content development involving issues of audience and purpose
• HTML Station: HTML reference; includes demonstrations, tutorials, codes, specification summaries, techniques/technologies descriptions, and supporting information about hypertext markup language (HTML) and related technologies

NEWSGROUP

GenXTechno Tags: newsgroups, usenet, computer, soc, rec, sci

A usenet newsgroup is a repository usually within the Usenet system, for messages posted from many users in different locations. The term may be confusing to some, because it is usually a discussion group. Newsgroups are technically distinct from, but functionally similar to, discussion forums on the World Wide Web. Newsreader software is used to read newsgroups.
Usenet is a worldwide distributed Internet discussion system.
Typically, the newsgroup is focused on a particular topic of interest. Some newsgroups allow the posting of messages on a wide variety of themes, regarding anything a member chooses to discuss as on-topic, while others keep more strictly to their particular subject, frowning on off-topic postings. The news admin (the administrator of a news server) decides how long articles are kept on his server before being expired (deleted). Different servers will have different retention times for the same newsgroup; some may keep articles for as little as one or two weeks, others may hold them for many months. Some admins keep articles in local or technical newsgroups around longer than articles in other newsgroups.
There were seven original major hierarchies of usenet newsgroups, known as the "Big 7":

• comp.* — Discussion of computer-related topics
• news.* — Discussion of Usenet itself
• sci.* — Discussion of scientific subjects
• rec.* — Discussion of recreational activities (e.g. games and hobbies)
• soc.* — Socialising and discussion of social issues.
• talk.* — Discussion of contentious issues such as religion and politics.
• misc.* — Miscellaneous discussion—anything which doesn't fit in the other hierarchies.

In 1995, humanities.* was created for the discussion of the humanities (e.g. literature, philosophy), and the Big 7 became the Big 8.
There are a number of newsgroup hierarchies outside of the Big 8 (and alt.*) that can be found at many news servers. These include non-English language groups, groups managed by companies or organizations about their products, geographic/local hierarchies, and even non-internet network boards routed into NNTP. Examples include (alphabetically):

• aus.* — Australian news groups
• ba.* — Discussion in the San Francisco Bay area
• ca.* — Discussion in California
• can.* — Canadian news groups
• cn.* — Chinese news groups
• chi.* — Discussions about the Chicago area
• de.* — Discussions in German
• england.* — Discussions (mostly) local to England, see also uk.*
• fidonet.* — Discussions routed from FidoNet
• fr.* — Discussions in French
• fj.* — "From Japan," discussions in Japanese
• gnu.* — Discussions about GNU software
• hawaii.* — Discussions (mostly) local to Hawaii
• hp.* — Hewlett-Packard internal news groups
• it.* — Discussions in Italian
• microsoft.* — Discussions about Microsoft products
• pl.* — Polish news groups
• tw.* — Taiwan news groups
• uk.* — Discussions on matters in the UK
• yale.* — Discussions (mostly) local to Yale

The main motive behind the formation of these groups is socializing and extending the network in the internet domain. Countless Indian newsgroups have popped up in the cyber space. Introduce yourself to the newsgroups of India and delve deep into their functions by visiting the following 10 portals:
indiatimes.com:
This website gives us an overview about the concept of Newsgroups, why such groups are increasingly gaining importance day after day and participation in such groups. It also discusses about the concept of Usenet where people all over the globe can participate in discussions. It also comes up with the terminology of Usenet. Another important area which has been covered by this website is the top level categories of Usenet like computer hardware, social issues, debates, recreational activities, humanities to name a few.
pathoindia.com:
The main aim behind the preparation of this Newsgroup is to enable the pathologists find useful resources over the internet. It also enables them to put their ideas over the Web. Even Pathologists from the most remote parts of the world can now communicate with his professional colleagues in a very easy manner. Here you will find mailing lists, tips for posting messages in a newsgroup and many other aspects.
rediff.com:
Rediff is a hugely popular newsgroup due to its versatile offerings. The main aim of this newsgroup is to make unknown people known to each other via the internet. Here you can search for people from your city, school, college, industry or from some other part of the country and socialize with them easily. All you need to enter into this newsgroup is a valid rediffmail id and it is totally free of any cost. Here you can search for other persons and even fill in their scrapbooks.
mastindia.com:
Are you in search of latest as well as medieval cultural news from world? If your answer to the above question is yes, then you need to visit this newsgroup which will provide you with the latest updated news from the world of arts. Here you will find several topics regarding Indian arts and what others have to say about those. Some of the popular topics that are offered here include culture of Karnataka, culture of Kerala, Tamil culture, collection of artistic articles and many more. It also offers some threads in religion like Hinduism, Buddhism and Jainism to name a few.
gadnet.com:
This newsgroup is entirely concerned about the Indian as well as the international sports arena. Here just by the click of a mouse, you can enter the discussion forum and post your valuable comments regarding a particular article. Apart from it here you also come to know about the feelings of other sports lovers regarding a particular game or a particular player. So if you are obsessed with sports and want to explore new horizons in the same, then this is indeed the best place for you on the Web.
rajiv.com:
Introduce yourself to the different Indian newsgroups by visiting this portal. This portal aims at exposing you to all the Usenet newsgroups of India. Specific categorization has been made to showcase the regional news communities of India. Want to meet the religious newsgroups of India – a simple click of the mouse and you will get acquainted with the spiritual and religious communities of India – go ahead and check-them out. This portal also offers answers to the most frequently asked questions (FAQs) on the newsgroups with utmost precision and details – clear all your doubts by looking at the answers.
search4i.com:
Are you an avid sports fan? Then this portal is a must-visit for you, drop in at this portal and acquaint yourself with the sports newsgroups of India. Click on the Indian sports newsgroups and there you can find a comprehensive list of the table tennis newsgroups of India. Are you looking for sports equipments? Here you will also find the website of the manufacturers of sports goods. Collect your sports goodies by logging on to this portal. The USP of this portal is its search tool. Look-up for any topic you want by accessing the search-box.
india.com:
Explore the multiple newsgroups of India by stopping by this portal. It has undertaken a sincere endeavor to bring all the different newsgroups of India under one umbrella. The site hosts a comprehensive collection of the Indian newsgroups ranging from religious to regional, sports to medicine and from music to health. So what are you waiting for- click and enter into your preferred realm. If you have any query regarding any newsgroup clear your doubts by checking –out the answers to the FAQs hosted on this portal.

Internet address

GenXTechno Tags: internet address, ip, ips, ip address, static ip, dynamic ip, logical ip, physical ip, dns

There are two kinds of addresses that are widely used on the Internet. One is a person's e-mail address, and the other is the address of a Web site, which is known as a URL. Following is an explanation of Internet e-mail addresses only. For more on URLs, see URL and Internet domain name.

E-Mail Address Format

The format for addressing a message to an Internet user is USER NAME @ DOMAIN NAME. For example, the address of the author of this database is dinesh@gmail.com. There are no spaces between any of the words. DINESH is the user name and GMAIL.COM is the domain name. The .COM stands for the commercial top level domain category (see Internet domain name). For the actual structure of an Internet address, see IP address.

IP Address

(Internet Protocol address) The address of a device attached to an IP network (TCP/IP network). Every client, server and network device is assigned an IP address, and every IP packet traversing an IP network contains a source IP address and a destination IP address.

Every IP address that is exposed to the public Internet is unique. In contrast, IP addresses within a local network use the same private addresses; thus, a user's computer in company A can have the same address as a user in company B and thousands of other companies. However, private IP addresses are not reachable from the outside world.

Logical Vs. Physical

An IP address is a logical address that is assigned by software residing in a server or router. In order to locate a device in the network, the logical IP address is converted to a physical address by a function within the TCP/IP protocol software. The physical address is actually built into the hardware.

Static and Dynamic IP

Network infrastructure devices such as servers, routers and firewalls are typically assigned permanent "static" IP addresses. The client machines can also be assigned static IPs by a network administrator, but most often are automatically assigned temporary "dynamic" IP addresses via software that uses the "dynamic host configuration protocol". Cable and DSL modems typically use dynamic IP with a new IP address assigned to the modem each time it is rebooted.

The Dotted Decimal Address: x.x.x.x

IP addresses are written in "dotted decimal" notation, which is four sets of numbers separated by decimal points; for example, 204.171.64.2. Instead of the domain name of a Web site, the actual IP address can be entered into the browser. However, the Domain Name System (DNS) exists so users can enter computerlanguage.com instead of an IP address, and the domain (the URL) computerlanguage.com is converted to the numeric IP address.

Class A, B and C

Based on the split of the 32 bits, an IP address is either Class A, B or C, the most common of which is Class C. More than two million Class C addresses are assigned, quite often in large blocks to network access providers for use by their customers. The fewest are Class A networks, which are reserved for government agencies and huge companies.

Although people identify the class by the first number in the IP address (see table below), a computer identifies class by the first three bits of the IP address (A=0; B=10; C=110). This class system has also been greatly expanded, eliminating the huge disparity in the number of hosts that each class can accommodate.

 NETWORKS VERSUS HOSTS IN IPV4 IP ADDRESSES

                  Maximum   Maximum    Number of

        Class     Number    Hosts      Bits used in

        Number    of        per        Network/Host

 Class  Range     Networks  Network    ID      ID

 A      1-126          127  16,777,214    7/24

 B      128-191     16,383      65,534   14/16

 C      192-223  2,097,151         254   21/8

        127 reserved for loopback test

An IP address is first divided between networks and hosts. The host bits are further divided between subnets and hosts. See subnet mask.

Domain Name

A name that identifies one or more IP addresses. For example, the domain name microsoft.com represents about a dozen IP addresses. Domain names are used in URLs to identify particular Web pages. For example, in the URL

http://www.pcwebopedia.com/index.html, the domain name is pcwebopedia.com.

Every domain name has a suffix that indicates which top level domain (TLD) it belongs to. There are only a limited number of such domains. For example:

· gov - Government agencies

· edu - Educational institutions

· org - Organizations (nonprofit)

· mil - Military

· com - commercial business

· net - Network organizations

· ca - Canada

· th - Thailand

Because the Internet is based on IP addresses, not on domain names, every Web server requires a Domain Name System (DNS) server to translate domain names into IP addresses.

Internet Protocol version 6 (IPv6)

It is the next-generation Internet Protocol version designated as the successor to IPv4, the first implementation used in the Internet that is still in dominant use currently. It is an Internet Layer protocol for packet-switched internetworks. The main driving force for the redesign of Internet Protocol is the foreseeable IPv4 address exhaustion. IPv6 was defined in December 1998 by the Internet Engineering Task Force (IETF) with the publication of an Internet standard specification.

Features and differences from IPv4

In most regards, IPv6 is a conservative extension of IPv4. Most transport- and application-layer protocols need little or no change to operate over IPv6; exceptions are application protocols that embed network-layer addresses, such as FTP or NTPv3 (Network Time Protocol).

Larger address space

The most important feature of IPv6 is a much larger address space than that of IPv4: addresses in IPv6 are 128 bits long, compared to 32-bit addresses in IPv4.

The very large IPv6 address space supports a total of 2¹²⁸ (about 3.4×10³⁸) addresses—or approximately 5×10²⁸ (roughly 2⁹⁵) addresses for each of the roughly 6.5 billion (6.5×10⁹) people alive in 2006.

Stateless address auto configuration

IPv6 hosts can configure themselves automatically when connected to a routed IPv6 network using ICMPv6 router discovery messages. When first connected to a network, a host sends a link-local multicast router solicitation request for its configuration parameters; if configured suitably, routers respond to such a request with a router advertisement packet that contains network-layer configuration parameters.

If IPv6 stateless address auto configuration is unsuitable for an application, a network may use stateful configuration with the Dynamic Host Configuration Protocol for IPv6 (DHCPv6) or hosts may be configured statically.

Multicast

Multicast, the ability to send a single packet to multiple destinations, is part of the base specification in IPv6. This is unlike IPv4, where it is optional (although usually implemented).

IPv6 does not implement broadcast, which is the ability to send a packet to all hosts on the attached link. The same effect can be achieved by sending a packet to the link-local all hosts multicast group. It therefore lacks the notion of a broadcast address—the highest address in a subnet (the broadcast address for that subnet in IPv4) is considered a normal address in IPv6.

Types of Internet Connections

GenXTechno Tags: Internet, connections, isdn, dsl, adsl, wi fi

Analog (up to 56k)
Also called dial-up access, it is both economical and slow. Using a modem connected to your PC, users connect to the Internet when the computer dials a phone number (which is provided by your ISP) and connects to the network. Dial-up is an analog connection because data is sent over an analog,  public telephone network. The modem converts received analog data to digital and vise versa. Because dial-up access uses normal telephone lines the quality of the connection is not always good and data rates are limited.
· Typical Dial-up connection speeds range from 2400 bps to 56 Kbps.
ISDN
Integrated services digital network (ISDN) is an international communications standard for sending voice, video, and data over digital telephone lines or normal telephone wires.
· Typical ISDN speeds range from 64 Kbps to 128 Kbps.
B-ISDN
Broadband ISDN is similar in function to ISDN but it transfers data over fiber optic telephone lines, not normal telephone wires. SONET is the physical transport backbone of B-ISDN. Broadband ISDN has not been widely implemented.
DSL
DSL is also called an always on connection because it uses existing 2-wire copper telephone line connected to the premise and will not tie up your phone as a dial-up connection does. There is no need to dial-in to your ISP as DSL is always on. The two main categories of DSL for home subscribers are called ADSL and SDSL.
ADSL
ADSL is the most commonly deployed types of DSL in North America. Short for asymmetric digital subscriber line ADSL supports data rates of from 1.5 to 9 Mbps when receiving data (known as the downstream rate) and from 16 to 640 Kbps when sending data (known as the upstream rate). ADSL requires a special ADSL modem.
ADSL+2
ADSL+2A is an extension to ADSL broadband technology that provides subscribers with significantly faster download speeds when compared to traditional ADSL connections. ADSL+2 works in the same fashion as ADSL a special filter is installed on a subscriber's telephone line to split existing copper telephone lines (POTS) between regular telephone (voice) and ADSL+2. ADSL2+ service is most commonly offered in highly-populated metropolitan areas and subscribers must be in close geographical locations to the provider's central office to receive ADSL2+ service.
SDSL
SDSL is still more common in Europe. Short for symmetric digital subscriber line, a technology that allows more data to be sent over existing copper telephone lines (POTS). SDSL supports data rates up to 3 Mbps. SDSL works by sending digital pulses in the high-frequency area of telephone wires and can not operate simultaneously with voice connections over the same wires. SDSL requires a special SDSL modem. SDSL is called symmetric because it supports the same data rates for upstream and downstream traffic.
VDSL
Very High DSL (VDSL) is a DSL technology that offers fast data rates over relatively short distances — the shorter the distance, the faster the connection rate.
· All types of DSL technologies are collectively referred to as xDSL.
· xDSL connection speeds range from 128 Kbps to 8 Mbps.
Cable
Through the use of a cable modem you can have a broadband Internet connection that is designed to operate over cable TV lines. Cable Internet works by using TV channel space for data transmission, with certain channels used for downstream transmission, and other channels for upstream transmission. Because the coaxial cable used by cable TV provides much greater bandwidth than telephone lines, a cable modem can be used to achieve extremely fast access.
· Cable speeds range from 512 Kbps to 20 Mbps.
Wireless Internet Connections
Wireless Internet, or wireless broadband is one of the newest Internet connection types. Instead of using telephone or cable networks for your Internet connection, you use radio frequency bands. Wireless Internet provides an always-on connection which can be accessed from anywhere — as long as you geographically within a network coverage area. Wireless access is still considered to be relatively new, and it may be difficult to find a wireless service provider in some areas. It is typically more expensive and mainly available in metropolitan areas.
· See the Wireless Networking Standards page of Webopedia for data rates, Modulation schemes, Security, and More info on Wireless networking.
T-1 Lines
T-1 lines are a popular leased line option for businesses connecting to the Internet and for Internet Service Providers (ISPs) connecting to the Internet backbone. It is a dedicated phone connection supporting data rates of 1.544Mbps.  A T-1 line actually consists of 24 individual channels, each of which supports 64Kbits per second. Each 64Kbit/second channel can be configured to carry voice or data traffic. Most telephone companies allow you to buy just one or some of these individual channels. This is known as as fractional T-1 access.
Bonded T-1
A bonded T-1 is two or more T-1 lines that have been joined (bonded) together to increase bandwidth. Where a single T-1 provides approximately 1.5Mbps, two bonded T1s provide 3Mbps or 46 channels for voice or data. Two bonded T-1s allow you to use the full bandwidth of 3Mbps where two individual T-1s can still only use a maximum of 1.5Mbps at one time. To be bonded the T-1 must run into the same router at the end, meaning they must run to the same ISP.
· T-1 Lines support speeds of 1.544 Mbps
· Fractional T-1 speeds are 64 Kbps per channel (up to 1.544 Mbps), depending on number of leased channels.
· Typical Bonded T-1 (two bonded T-1 lines) speed is around 3 Mbps.
T-3 Lines
T-3 lines are dedicated phone connections supporting data rates of about 43 to 45 Mbps. It too is a popular leased line option. A T-3 line actually consists of 672 individual channels, each of which supports 64 Kbps. T-3 lines are used mainly by Internet Service Providers (ISPs) connecting to the Internet backbone and for the backbone itself.
· Typical T-3 supports speeds ranging from 43 to 45 Mbps.

OC3
Short for Optical Carrier, level 3 it is used to specify the speed of fiber optic networks conforming to the SONET standard. OC3 is typically used as a fiber optic backbone for large networks with large voice, data, video, and traffic needs.
· Speeds are 155.52 Mbps, or roughly the speed of 100 T1 lines.
Satellite
Internet over Satellite (IoS) allows a user to access the Internet via a satellite that orbits the earth. A satellite is placed at a static point above the earth's surface, in a fixed position. Because of the enormous distances signals must travel from the earth up to the satellite and back again, IoS is slightly slower than high-speed terrestrial connections over copper or fiber optic cables.

HTML TAGS

GenXTechno Tags: html, web, development, tags

Below is a complete list of HTML tags from the HTML 4.01 specification. The HTML tags are listed according to relatively relation with previous tab to help you quickly find the tag you're looking for.
Click on link to download the file.
http://www.mediafire.com/file/9x2qga2a2c3g82x/HTML%20tags_Net.pdf

Multipurpose Internet Mail Extensions

GenXTechno Tags: mime, mail, extensions, computer, internet

MIME Types

MIME (Multipurpose Internet Mail Extensions) is an Internet standard for describes message content types.
MIME is a standard for describing different types of information This was originally meant to be used to specify encoding for different types of information into text. This made it possible to send them as e-mail.
The standard MIME is also used in other types of communication where there is a need for specifying which type of information is used. This could be your local operating system or a web server.
MIME defines mechanisms for sending other kinds of information in e-mail. These include text in languages other than English using character encodings other than ASCII, and 8-bit binary content such as files containing images, sounds, movies, and computer programs. MIME is also a fundamental component of communication protocols such as HTTP, which requires that data be transmitted in the context of e-mail-like messages even though the data might not (and usually doesn't) actually have anything to do with e-mail. Mapping messages into and out of MIME format is typically done automatically by an e-mail client or by mail servers when sending or receiving Internet (SMTP/MIME) e-mail.
How do I read MIME in my mail?
Mime is just a specification. Normally the information is encoded with some other standard format. When decoded it regains it original shape.
To be able to read the file you need an application that can handle the attached file. If two files, a word document and a image is sent by email they would both get encoded as mime. Upon receiving these files there need to be an application associated with each file type. Microsoft word or maybe another word processor would be associated with the word document making it possible to read the file. Photoshop or another image viewer would be associated with the image.
Normally the conversion from MIME to files is handled by the e-mail application. When the file is stored on disk it is up to the operating system to map an application to file type.
MIME messages can contain text, images, audio, video, and other application-specific data.
Official MIME info is provided by the Internet Engineering Task Force (IETF) in the following documents:

• RFC-822   Standard for ARPA Internet text messages
• RFC-2045 MIME Part 1: Format of Internet Message Bodies
• RFC-2046 MIME Part 2: Media Types
• RFC-2047 MIME Part 3: Header Extensions for Non-ASCII Text
• RFC-2048 MIME Part 4: Registration Procedures
• RFC-2049 MIME Part 5: Conformance Criteria and Examples

Different applications support different MIME types.
The reference below is a list of MIME types supported by Microsoft Internet Information Server version 5.

---

MIME Types

MIME Types (Application):

Type/sub-type	Extension
application/envoy	evy
application/fractals	fif
application/futuresplash	spl
application/hta	hta
application/internet-property-stream	acx
application/mac-binhex40	hqx
application/msword	doc
application/msword	dot
application/octet-stream	*
application/octet-stream	bin
application/octet-stream	class
application/octet-stream	dms
application/octet-stream	exe
application/octet-stream	lha
application/octet-stream	lzh
application/oda	oda
application/olescript	axs
application/pdf	pdf
application/pics-rules	prf
application/pkcs10	p10
application/pkix-crl	crl
application/postscript	ai
application/postscript	eps
application/postscript	ps
application/rtf	rtf
application/set-payment-initiation	setpay
application/set-registration-initiation	setreg
application/vnd.ms-excel	xla
application/vnd.ms-excel	xlc
application/vnd.ms-excel	xlm
application/vnd.ms-excel	xls
application/vnd.ms-excel	xlt
application/vnd.ms-excel	xlw
application/vnd.ms-outlook	msg
application/vnd.ms-pkicertstore	sst
application/vnd.ms-pkiseccat	cat
application/vnd.ms-pkistl	stl
application/vnd.ms-powerpoint	pot
application/vnd.ms-powerpoint	pps
application/vnd.ms-powerpoint	ppt
application/vnd.ms-project	mpp
application/vnd.ms-works	wcm
application/vnd.ms-works	wdb
application/vnd.ms-works	wks
application/vnd.ms-works	wps
application/winhlp	hlp
application/x-bcpio	bcpio
application/x-cdf	cdf
application/x-compress	z
application/x-compressed	tgz
application/x-cpio	cpio
application/x-csh	csh
application/x-director	dcr
application/x-director	dir
application/x-director	dxr
application/x-dvi	dvi
application/x-gtar	gtar
application/x-gzip	gz
application/x-hdf	hdf
application/x-internet-signup	ins
application/x-internet-signup	isp
application/x-iphone	iii
application/x-javascript	js
application/x-latex	latex
application/x-msaccess	mdb
application/x-mscardfile	crd
application/x-msclip	clp
application/x-msdownload	dll
application/x-msmediaview	m13
application/x-msmediaview	m14
application/x-msmediaview	mvb
application/x-msmetafile	wmf
application/x-msmoney	mny
application/x-mspublisher	pub
application/x-msschedule	scd
application/x-msterminal	trm
application/x-mswrite	wri
application/x-netcdf	cdf
application/x-netcdf	nc
application/x-perfmon	pma
application/x-perfmon	pmc
application/x-perfmon	pml
application/x-perfmon	pmr
application/x-perfmon	pmw
application/x-pkcs12	p12
application/x-pkcs12	pfx
application/x-pkcs7-certificates	p7b
application/x-pkcs7-certificates	spc
application/x-pkcs7-certreqresp	p7r
application/x-pkcs7-mime	p7c
application/x-pkcs7-mime	p7m
application/x-pkcs7-signature	p7s
application/x-sh	sh
application/x-shar	shar
application/x-shockwave-flash	swf
application/x-stuffit	sit
application/x-sv4cpio	sv4cpio
application/x-sv4crc	sv4crc
application/x-tar	tar
application/x-tcl	tcl
application/x-tex	tex
application/x-texinfo	texi
application/x-texinfo	texinfo
application/x-troff	roff
application/x-troff	t
application/x-troff	tr
application/x-troff-man	man
application/x-troff-me	me
application/x-troff-ms	ms
application/x-ustar	ustar
application/x-wais-source	src
application/x-x509-ca-cert	cer
application/x-x509-ca-cert	crt
application/x-x509-ca-cert	der
application/ynd.ms-pkipko	pko
application/zip	zip

MIME Types (Audio):

audio/basic	au
audio/basic	snd
audio/mid	mid
audio/mid	rmi
audio/mpeg	mp3
audio/x-aiff	aif
audio/x-aiff	aifc
audio/x-aiff	aiff
audio/x-mpegurl	m3u
audio/x-pn-realaudio	ra
audio/x-pn-realaudio	ram
audio/x-wav	wav

MIME Types (Image):

image/bmp	bmp
image/cis-cod	cod
image/gif	gif
image/ief	ief
image/jpeg	jpe
image/jpeg	jpeg
image/jpeg	jpg
image/pipeg	jfif
image/svg+xml	svg
image/tiff	tif
image/tiff	tiff
image/x-cmu-raster	ras
image/x-cmx	cmx
image/x-icon	ico
image/x-portable-anymap	pnm
image/x-portable-bitmap	pbm
image/x-portable-graymap	pgm
image/x-portable-pixmap	ppm
image/x-rgb	rgb
image/x-xbitmap	xbm
image/x-xpixmap	xpm
image/x-xwindowdump	xwd

MIME Types (Message):

message/rfc822	mht
message/rfc822	mhtml
message/rfc822	nws

MIME Types (Text):

text/css	css
text/h323	323
text/html	htm
text/html	html
text/html	stm
text/iuls	uls
text/plain	bas
text/plain	c
text/plain	h
text/plain	txt
text/richtext	rtx
text/scriptlet	sct
text/tab-separated-values	tsv
text/webviewhtml	htt
text/x-component	htc
text/x-setext	etx
text/x-vcard	vcf

MIME Types (Video):

video/mpeg	mp2
video/mpeg	mpa
video/mpeg	mpe
video/mpeg	mpeg
video/mpeg	mpg
video/mpeg	mpv2
video/quicktime	mov
video/quicktime	qt
video/x-la-asf	lsf
video/x-la-asf	lsx
video/x-ms-asf	asf
video/x-ms-asf	asr
video/x-ms-asf	asx
video/x-msvideo	avi
video/x-sgi-movie	movie

MIME Types (Video):

x-world/x-vrml	flr
x-world/x-vrml	vrml
x-world/x-vrml	wrl
x-world/x-vrml	wrz
x-world/x-vrml	xaf
x-world/x-vrml	xof

---

Mime Types By File Extension

Extension	Type/sub-type
	application/octet-stream
323	text/h323
acx	application/internet-property-stream
ai	application/postscript
aif	audio/x-aiff
aifc	audio/x-aiff
aiff	audio/x-aiff
asf	video/x-ms-asf
asr	video/x-ms-asf
asx	video/x-ms-asf
au	audio/basic
avi	video/x-msvideo
axs	application/olescript
bas	text/plain
bcpio	application/x-bcpio
bin	application/octet-stream
bmp	image/bmp
c	text/plain
cat	application/vnd.ms-pkiseccat
cdf	application/x-cdf
cer	application/x-x509-ca-cert
class	application/octet-stream
clp	application/x-msclip
cmx	image/x-cmx
cod	image/cis-cod
cpio	application/x-cpio
crd	application/x-mscardfile
crl	application/pkix-crl
crt	application/x-x509-ca-cert
csh	application/x-csh
css	text/css
dcr	application/x-director
der	application/x-x509-ca-cert
dir	application/x-director
dll	application/x-msdownload
dms	application/octet-stream
doc	application/msword
dot	application/msword
dvi	application/x-dvi
dxr	application/x-director
eps	application/postscript
etx	text/x-setext
evy	application/envoy
exe	application/octet-stream
fif	application/fractals
flr	x-world/x-vrml
gif	image/gif
gtar	application/x-gtar
gz	application/x-gzip
h	text/plain
hdf	application/x-hdf
hlp	application/winhlp
hqx	application/mac-binhex40
hta	application/hta
htc	text/x-component
htm	text/html
html	text/html
htt	text/webviewhtml
ico	image/x-icon
ief	image/ief
iii	application/x-iphone
ins	application/x-internet-signup
isp	application/x-internet-signup
jfif	image/pipeg
jpe	image/jpeg
jpeg	image/jpeg
jpg	image/jpeg
js	application/x-javascript
latex	application/x-latex
lha	application/octet-stream
lsf	video/x-la-asf
lsx	video/x-la-asf
lzh	application/octet-stream
m13	application/x-msmediaview
m14	application/x-msmediaview
m3u	audio/x-mpegurl
man	application/x-troff-man
mdb	application/x-msaccess
me	application/x-troff-me
mht	message/rfc822
mhtml	message/rfc822
mid	audio/mid
mny	application/x-msmoney
mov	video/quicktime
movie	video/x-sgi-movie
mp2	video/mpeg
mp3	audio/mpeg
mpa	video/mpeg
mpe	video/mpeg
mpeg	video/mpeg
mpg	video/mpeg
mpp	application/vnd.ms-project
mpv2	video/mpeg
ms	application/x-troff-ms
mvb	application/x-msmediaview
nws	message/rfc822
oda	application/oda
p10	application/pkcs10
p12	application/x-pkcs12
p7b	application/x-pkcs7-certificates
p7c	application/x-pkcs7-mime
p7m	application/x-pkcs7-mime
p7r	application/x-pkcs7-certreqresp
p7s	application/x-pkcs7-signature
pbm	image/x-portable-bitmap
pdf	application/pdf
pfx	application/x-pkcs12
pgm	image/x-portable-graymap
pko	application/ynd.ms-pkipko
pma	application/x-perfmon
pmc	application/x-perfmon
pml	application/x-perfmon
pmr	application/x-perfmon
pmw	application/x-perfmon
pnm	image/x-portable-anymap
pot,	application/vnd.ms-powerpoint
ppm	image/x-portable-pixmap
pps	application/vnd.ms-powerpoint
ppt	application/vnd.ms-powerpoint
prf	application/pics-rules
ps	application/postscript
pub	application/x-mspublisher
qt	video/quicktime
ra	audio/x-pn-realaudio
ram	audio/x-pn-realaudio
ras	image/x-cmu-raster
rgb	image/x-rgb
rmi	audio/mid
roff	application/x-troff
rtf	application/rtf
rtx	text/richtext
scd	application/x-msschedule
sct	text/scriptlet
setpay	application/set-payment-initiation
setreg	application/set-registration-initiation
sh	application/x-sh
shar	application/x-shar
sit	application/x-stuffit
snd	audio/basic
spc	application/x-pkcs7-certificates
spl	application/futuresplash
src	application/x-wais-source
sst	application/vnd.ms-pkicertstore
stl	application/vnd.ms-pkistl
stm	text/html
svg	image/svg+xml
sv4cpio	application/x-sv4cpio
sv4crc	application/x-sv4crc
swf	application/x-shockwave-flash
t	application/x-troff
tar	application/x-tar
tcl	application/x-tcl
tex	application/x-tex
texi	application/x-texinfo
texinfo	application/x-texinfo
tgz	application/x-compressed
tif	image/tiff
tiff	image/tiff
tr	application/x-troff
trm	application/x-msterminal
tsv	text/tab-separated-values
txt	text/plain
uls	text/iuls
ustar	application/x-ustar
vcf	text/x-vcard
vrml	x-world/x-vrml
wav	audio/x-wav
wcm	application/vnd.ms-works
wdb	application/vnd.ms-works
wks	application/vnd.ms-works
wmf	application/x-msmetafile
wps	application/vnd.ms-works
wri	application/x-mswrite
wrl	x-world/x-vrml
wrz	x-world/x-vrml
xaf	x-world/x-vrml
xbm	image/x-xbitmap
xla	application/vnd.ms-excel
xlc	application/vnd.ms-excel
xlm	application/vnd.ms-excel
xls	application/vnd.ms-excel
xlt	application/vnd.ms-excel
xlw	application/vnd.ms-excel
xof	x-world/x-vrml
xpm	image/x-xpixmap
xwd	image/x-xwindowdump
z	application/x-compress
zip	application/zip

MIME Technical Summary

MIME is defined by an Internet standard document called RFC1521. This document summarizes the contents of RFC1521. Sufficient detail is presented here to understand the capabilities of MIME. For sufficient detail to implement MIME please read RFC1521.
MIME allows messages to contain multiple objects. When multiple objects are in a MIME message, they are represented in a form called a body part. A body part has a header and a body, so it makes sense to speak about the body of a body part. Also, body parts can be nested in bodies that contain one or multiple body parts.
The Content-Type values, subtypes, and parameter names defined in the MIME standard are case-insensitive. However, many parameter values are case sensitive
The MIME standard is written to allow MIME to be extended in certain ways, without having to revise the standard. MIME specifies sets of values that are allowed for various fields and parameters. The provides a procedure for extending these sets of values by registering them with an entity called the Internet Assigned Numbers Authority (IANA).