Internet, WWW, protocols, email, browsers, remote login, and file transfer
Internet: A global network of interconnected computers that communicate using standard protocols (TCP/IP). Often called the "network of networks."
WWW (World Wide Web): A system of interlinked hypertext documents (web pages) accessed via the Internet using a browser. WWW is a service that runs ON the Internet — not the same as the Internet itself!
Web Server: A computer that stores and serves web pages. When you type a URL, the web server sends the requested page to your browser.
Web Client: Your computer/device (with a browser) that requests web pages from the server.
Website: A collection of related web pages hosted at a domain (e.g., www.ncert.nic.in)
Web Page: A single HTML document displayed in a browser
Blog: A regularly updated website where an individual posts opinions/articles (web log)
Newsgroup: An online discussion forum where users post and reply to messages on specific topics
URL (Uniform Resource Locator): The address of a web page.
Format: protocol://domain-name/path
Example: https://www.ncert.nic.in/textbook/textbook.htm
• https:// — protocol used
• www.ncert.nic.in — domain name
• /textbook/textbook.htm — path to the specific file
Email Address: username@domain.extension (e.g., student@school.edu.in)
| Protocol | Full Form | Use |
|---|---|---|
| TCP/IP | Transmission Control Protocol / Internet Protocol | Foundation of Internet — breaks data into packets and routes them |
| HTTP | HyperText Transfer Protocol | Transferring web pages (unsecured) |
| HTTPS | HTTP Secure | Encrypted, secure version of HTTP (banking, shopping) |
| SMTP | Simple Mail Transfer Protocol | Sending emails from client to server |
| POP3 | Post Office Protocol v3 | Receiving emails — downloads from server to local device |
| IMAP | Internet Message Access Protocol | Receiving emails — keeps them on server (access from multiple devices) |
| Protocol | Full Form | Use |
|---|---|---|
| FTP | File Transfer Protocol | Upload/download files to/from a remote server (not encrypted) |
| SFTP | SSH File Transfer Protocol | Secure file transfer (encrypted via SSH) |
| SCP | Secure Copy Protocol | Securely copy files between hosts using SSH |
| SSH | Secure Shell | Securely log in and run commands on a remote computer (encrypted) |
| TELNET | Teletype Network | Remote login to a computer (not encrypted — obsolete) |