ExamCourses.in
Internet, Networking and Email Basics
Internet = global network of networks using TCP/IP; WWW = hypertext service running on the Internet. Networks classified by range: PAN < LAN < MAN < WAN. Devices: Router (between networks), Switch (within LAN, MAC-based), Hub (broadcasts to all), Modem (digital-analog conversion). IP address uniquely identifies a device (IPv4 32-bit, IPv6 128-bit); DNS maps domain names to IP addresses. Email uses To/CC/BCC fields; SMTP sends mail, POP3 downloads-and-removes from server, IMAP syncs across devices while retaining mail on the server.
Important topics
- Internet vs World Wide Web: Internet is the network infrastructure, WWW is a service (hypertext documents) that runs over it
- Network types by range: PAN, LAN, MAN, WAN
- Networking devices: Router, Switch, Hub, Modem and their distinct roles
- IP address (IPv4 32-bit vs IPv6 128-bit) as a unique device identifier
- DNS translates human-readable domain names into numerical IP addresses
- Email fields: To, CC (visible copy), BCC (hidden copy), Subject, Attachment
- Email protocols: SMTP (sending), POP3 (download & remove), IMAP (sync across devices)
- URL structure: protocol + domain name + path