Understanding the Internet and its Services

Posted on Oct 24, 2024 in Computers

1. What is the Internet?

The internet is a decentralized network of interconnected communication networks using the TCP/IP protocol family. This allows diverse physical networks to function as a single, global logical network. Its origins trace back to 1969 with the creation of ARPANET, initially used for defense communication during wartime in the USA.

While often confused, the internet and the World Wide Web (WWW) are distinct. The WWW, developed in 1990, is a set of protocols enabling easy access to hypertext files remotely, using the internet as its transmission medium.

2. Internet Services

Internet services are the facilities provided by the internet. Each service offers a unique way to utilize the network. Understanding the range of internet services allows users to select those most relevant to their needs.

Popular internet services include: Email, WWW, FTP, Newsgroups, IRC, and Telephony Services.

3. Email

Email allows users to send electronic letters to others with internet access. These messages are stored until retrieved by the recipient. Email is significantly faster and cheaper than traditional mail, enabling communication with anyone worldwide who has internet access.

4. The @ Symbol in Email Addresses

The “@” symbol separates the username from the domain name in an email address (e.g., name@domain.net). Its use originated from its meaning as an abbreviation of “at” in English.

Ray Tomlinson, the inventor of email, popularized the “@” symbol in the 1970s. He chose it due to its presence on all keyboards. At the time, other symbols like “::” and “t” were also considered.

5. Real-Time Communication Protocols

TCP/IP

TCP/IP (Transmission Control Protocol/Internet Protocol) is a suite of protocols governing internet communication. It relies on IP addresses assigned to each computer on the network to route data packets.

Developed for military purposes, TCP/IP is designed to:

• Divide messages into packets
• Use an addressing system
• Route data across the network
• Detect errors in data transmissions

ATM (Asynchronous Transfer Mode)

ATM is a network technology for high-speed data transfer. It uses 53-byte cells to transmit voice, data, and video simultaneously over the same cable.

6. IRC and MUD Clients

mIRC

mIRC is a popular Windows-based IRC client, distributed as shareware. It features an advanced scripting language and file-sharing capabilities via the DCC protocol.

MUD

MUD is an early client/server application.

TALK

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7. FTP Connection and Transfer Types

Connection Types

• Active Mode: Presents security risks due to the use of insecure ports.
• Passive Mode: Recommended for enhanced security as it utilizes secure ports and bypasses filters and antivirus software.

Transfer Types

• ASCII: Suitable for transferring files containing only printable characters (e.g., HTML pages, but not images).
• Binary: Used for compressed files, executables, images, audio files, etc.

8. FTP Clients

An FTP client is a program installed on a user’s computer that uses the FTP protocol to connect to an FTP server and transfer files (upload or download).

Using an FTP client requires knowing the filename, server address (for downloading), destination computer (for uploading), and the relevant folder.

Examples of FTP clients: CuteFTP, FileZilla.

9. Archie and Veronica

Archie (named after “archive”) was a system for locating files and directories on FTP servers. It acted as a database of filenames and FTP server locations. Like Gopher, it has largely been replaced by the WWW.

Archie, created in 1990 by Alan Emtage, Bill Heelan, and Peter J. Deutsch at McGill University, was the first search engine. It indexed FTP archives, enabling users to find specific files.

Veronica (Very Easy Rodent-Oriented Net-wide Index to Computer Archives) searched for words within the menu titles of Gopher servers worldwide.