Data Communication & Networks · 2025–26

DCN Practical Exam Kit

Ten selected experiments · aim, procedure, runnable code, illustrated output and result

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Experiment 10 — DNS Queries and HTTP/HTTPS Requests

Manual pages: 89–91 | Tools: Command Prompt, Chrome DevTools; optional Postman

AIM

To test DNS queries and HTTP/HTTPS requests and study domain-name resolution and client–server request/response behavior.

PART A — DNS EXECUTION

  1. Open Windows Command Prompt (Win + R → cmd).
  2. Run nslookup google.com. Note DNS server, domain and returned IP addresses.
  3. If dig is installed, run dig google.com and dig +short google.com (the second prints concise answers). dig is not included with Windows by default; lack of dig is not a network failure.

PART B — HTTP/HTTPS EXECUTION

  1. Chrome → open https://example.com → press F12 → Network tab.
  2. Ensure red recording dot is enabled; refresh the page. Click the example.com/Document request.
  3. Inspect Headers (Request URL, GET, Status Code), Response (HTML), Timing (timings); optional Doc / Fetch-XHR filters.
  4. Optional Postman practice, matching experiment title: new GET https://example.com → Send → examine status and HTML body. The manual's detailed procedural section specifically uses browser DevTools, not a complete Postman walkthrough.

COMMANDS

See WINDOWS_COMMANDS.txt.

EXPECTED OUTPUT

nslookup google.com => domain resolves to one or more IP addresses
Chrome Network: GET https://example.com/ -> HTTP 200 OK (if reachable)
Response: HTML document; Timing: request phases

RESULT

Thus, DNS resolution with nslookup/dig and HTTP/HTTPS request inspection using browser developer tools were demonstrated.

VIVA