Internet, Networking and Web Publishing
What this domain tests
How a request reaches a server, and how a finished site is hosted, addressed and published.
Core rules and concepts
- A URL names the scheme, host, port, path and query. DNS translates a domain into an IP address through records such as A (IPv4), AAAA (IPv6) and CNAME.
- TCP is reliable and connection-oriented; UDP is faster and connectionless. HTTP normally uses port 80, HTTPS port 443, and HTTPS wraps HTTP in TLS.
- Bandwidth is capacity; latency is delay. A high-bandwidth link can still feel slow if latency is high.
- Hosting types: shared, VPS, dedicated and cloud. A registrar sells the domain; the host stores the files. They are separate services.
- Publishing: upload to a server directory containing
index.html, set permissions, enable HTTPS, then test. Use a staging copy before production. - Caching and TTL explain why changes appear late; a CDN serves files from locations near the user.
Worked example
A user types a site address. Reasoning: the browser checks its cache, asks DNS for the A record, opens a TCP connection, negotiates TLS, sends GET /, receives 200 with HTML, then requests CSS and images. After the domain's IP changes, the old record may persist until its TTL expires, which is why some visitors still reach the old server.
Traps that cost marks
Confusing registrar with host; uploading files without an index.html; running a login form over plain HTTP; ignoring broken links and 404 pages; assuming a DNS change is instant.