Internet, Web Basics and Email
Tested: internet versus WWW, addressing and DNS, URL anatomy, browser versus search engine, basic HTML, and email fields and protocols.
Concepts
The Internet is the global network of networks; the World Wide Web is one service running on it - hyperlinked documents. An IP address identifies a device (IPv4 has four octets, each 0–255, e.g. 192.168.1.10); DNS converts a domain name into an IP address; an ISP provides the connection. HTTP (port 80) transfers web pages, HTTPS (443) adds encryption; SMTP sends mail, POP3/IMAP receives it; FTP transfers files.
URL anatomy
https://www.example.org/notes/it.html → scheme https, host www.example.org, path /notes/, file it.html.
Browser versus search engine
Chrome, Firefox and Edge are browsers; Google, Bing and DuckDuckGo are search engines reached through a browser. A search query is not a URL, and the browser is not the Internet.
An address is local-part@domain. To holds the main recipients; Cc holds visible copies; Bcc holds hidden copies; attachments are encoded files. Never open an unexpected attachment; check the sender's domain for phishing.
Worked example
One mail must reach 40 parents so that no parent sees another's address. Reasoning: put all 40 addresses in Bcc and address the To field to yourself or an official id. Using To or Cc would expose every address to every recipient, which is a privacy breach; if replies must reach a colleague, set Reply-To rather than adding them to To.
Basic HTML
Tags mark structure: , , , <body>, <h1>, <p>, <a href="...">, <img src="...">, <ul><li>. Most tags need a closing tag.</p> <h3>Traps</h3> <ul> <li>Saying www is the protocol, or that HTTPS is a different page format.</li> <li>Confusing download (to your device) with upload (to the server).</li> <li>Confusing a bookmark (saved address) with a hyperlink (clickable reference).</li> </ul>