Addresses, ports, and the first server

Quick check: can you name your LAN IP, start the server, read a status code, and say what just happened on the phone?

Pass at 70%. Feedback appears as you go, and only your first answer to each question counts.

Question 1 of 6

Place 172.18.4.10 in an RFC 1918 block.

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Answer:

172.16.0.0/12 (addresses 172.16.0.0172.31.255.255).

A full-credit answer shows: A strong answer names the 172.16.0.0/12 block (or the range 172.16–172.31).

The middle private block is 172.16/12, not 172/8. 172.18 sits inside it (objective 2).

Question 2 of 6

An ss -tlnp line ends with 0.0.0.0:8000 and users:(("python3",pid=8,fd=4)). What is listening, and on which door?

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Answer:

python3 is listening on port 8000 on all interfaces (0.0.0.0).

A full-credit answer shows: A strong answer covers: (1) the process is python3; (2) the port is 8000; (3) 0.0.0.0 means all interfaces, not just loopback.

Address:port is the door. The process column names the program. 0.0.0.0 is every interface, which matters in the next unit (objective 6).

Question 3 of 6

A log line reads 127.0.0.1 - - [29/Jul/2026 04:26:16] "GET /nope HTTP/1.1" 404 -. What did the client ask for, and what happened?

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Answer:

The client asked for /nope with GET. The server answered 404 — that path is not a file in the folder being served.

A full-credit answer shows: A strong answer covers: (1) method GET; (2) path /nope; (3) status 404, meaning the path was missing.

Method, path, status. 404 is the client's wrong path, not a crashed server (objectives 8, 12).

Question 4 of 6

Split http://192.168.1.42:8000/ into scheme, host, port, and path.

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Answer:

scheme http, host 192.168.1.42, port 8000, path /.

A full-credit answer shows: A strong answer names all four: http, 192.168.1.42, 8000, /.

The IP is allowed in the host slot. :8000 is the door. / is the path the server maps to its folder (objective 10).

Question 5 of 6

The same index.html opened as file:// has no status code. Opened as http://localhost:8000 it has one.

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Answer: True

file:// is the browser reading a path. http:// is a conversation: request, status, headers, body. That is why the server exists (objective 9).

Question 6 of 6

In curl -v output, a line starting with > is something the server sent to you.

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Answer: False

The opposite is true. > is a line you sent (the request). < is a line the server sent (the response) (objective 11).

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