Web development Technologies overview v2023

Internet Technologies Overview

What is the WWW

  • The World Wide Web (WWW) is a system of interlinked hypertext documents accessed via the Internet.

  • Users can view web pages with multimedia and navigate through hyperlinks using web browsers.

  • Developed by Tim Berners-Lee at CERN in 1989, aiming to link and access various kinds of information.

Development of the WWW

  • The Web was intended as a pool for sharing human knowledge and culture.

  • It enabled a flexible format for spreading information and played a significant role in popularizing the Internet.

Difference Between WWW and Internet

  • The WWW is not synonymous with the Internet; it is a collection of documents and client/server software using protocols like TCP/IP and HTTP.

TCP/IP Connection

  • TCP/IP suite: set of communications protocols for the Internet, primarily Transmission Control Protocol (TCP) and Internet Protocol (IP).

  • Evolved from developments in the 1960s and 70s and became essential with the advent of the WWW in the early 1990s.

IPv4 & IPv6

IPv4

  • Internet Protocol version 4 (IPv4) is the most widely deployed version of the IP protocol.

  • Described in RFC 791, allowing about 4.3 billion addresses.

IPv6

  • Internet Protocol version 6 (IPv6) is designed to succeed IPv4, providing up to 2128 addresses.

  • Improvements over IPv4 are intended for long-term Internet growth.

Network Debugging Tools

Ping

  • Tool used to test host reachability in an IP network.

  • Sends ICMP echo request packets and measures round-trip time.

  • Outputs includes minimum, maximum, and average times, along with packet loss statistics.

Traceroute

  • Diagnostic tool showing the path packets take to a destination in an IP network.

  • Sends ICMP requests, measuring transit delays and identifying intermediate routers.

Nslookup

  • Command-line tool for querying the Domain Name System (DNS) to obtain domain names or IP addresses.

  • Used to verify DNS records and troubleshooting.

Whois

  • Protocol for querying databases of registered Internet resources.

  • Provides contact information and registration details of domains and IP addresses.

DNS (Domain Name System)

  • A hierarchical naming system for devices connected to the Internet, translating domain names to IP addresses.

  • Functions like a phone book, allowing easy human-friendly naming of resources.

  • Distributes responsibility for domain names and mapping through authoritative name servers.

Domain Name Registration

  • Managed by registrars accredited by ICANN.

  • Registrars maintain databases for the top-level domains and publish via the Whois protocol.

HTTP(S) Protocol

  • HTTP is a request-response protocol between a client (web browser) and a server.

  • Clients submit requests, servers respond with status information and requested content.

HTTP Methods

  • GET: Requests representation for specified resource.

  • POST: Submits data to be processed.

  • HEAD: Requests response without the body for metadata.

FTP(S) - File Transfer Protocol

  • Standard protocol for transferring files over a TCP network.

  • Supports anonymous and authenticated access, allows file transfers using client-server architecture.

Email Protocols

IMAP(S)

  • Internet Message Access Protocol allows email clients to access and manage email on remote servers.

  • Supports online/offline access, keeping messages on the server until deleted by the user.

POP3(S)

  • Post Office Protocol used by email clients to retrieve emails from a server, simpler than IMAP.

SMTP(S)

  • Simple Mail Transfer Protocol used for sending emails across networks.

  • Involves email submission by clients and retrieval from mail servers.