Assignment 1: Map the lab network

Goal: prove you can read a real machine's network configuration and reason about it — the skills from Lessons 1 and 2.

Where: SSH into the Jumpbox (your mentor will give you access). Everything here is read-only; you won't change anything.

Tasks

1. Find the Jumpbox's own IPv4 address and prefix (e.g. 10.100.100.254/24). Record the address, the prefix, the subnet mask in dotted-decimal, and the default gateway.
2. For the subnet the Jumpbox is on, write down: the network address, the broadcast address, and the range of usable host addresses. Show how you got them (by hand and/or with ipcalc).
3. Pick any two other lab hosts (e.g. Git-Server 10.100.100.2 and Docs-Server 10.100.100.3). State whether they are on the same network as the Jumpbox, and explain your reasoning in one sentence each.
4. Invent an address that is not on the lab subnet, and explain what the Jumpbox would do with a packet destined for it (local delivery or via the gateway — and why).
5. Resolve the docs site's hostname to an IP and confirm it matches a host you'd expect.

Deliverable

A short markdown note (paste it in your own scratch book in BookStack, or a file) containing:

• The four facts from task 1.
• Your subnet math from task 2.
• Your same-network / different-network judgements with reasoning.
• The command(s) you used for each answer.

Acceptance criteria — you're done when:

• You can state the Jumpbox's address and prefix, and explain what the prefix means in plain words.
• Your network address and broadcast address for the subnet are correct (check with ipcalc).
• Your usable-range count is 254, and you can say why it isn't 256.
• Each same-network/different-network judgement is correct and justified by comparing network parts, not guessed.
• For the off-subnet address, you correctly say the packet goes to the default gateway, and name the gateway IP.
• Every answer is backed by the actual command you ran (a grader could re-run it and get your result).

Hints

• ip addr, ip route, ipcalc <addr>/<prefix>, getent hosts <name>.
• Stuck for more than ~30 minutes after re-reading Lessons 1–2? Ask your mentor — but bring what you've tried.