Lab — Host & Port Discovery with a Network Scanner

Inventory the Larkfield branch subnet, then profile the catalog server's open services from the CLI.

N10-009 · 5.5 N10-009 · 1.4 APNET · 4.3 APNET · 4.2

netscan@ops-jumpbox:~ — branch survey

SCENARIO BRIEF

You are Marisol Okonkwo, a first-year network technician on the Larkfield Community Library IT co-op. The branch network (10.42.7.0/24) has no current documentation, and patrons are reporting the online catalog is "sometimes" unreachable.

Before troubleshooting, build an inventory: find which hosts are up, then profile the catalog server's open TCP ports and the services behind them — using only the scanner on the ops jumpbox.

Command reference (this simulated scanner)

nmap -sn <cidr>        host discovery / "ping" sweep, no port scan
nmap <ip>             scan common TCP ports on one host
nmap -p <list> <ip>   scan specific ports, e.g. -p 22,80,443
nmap -p- <ip>         scan all TCP ports
nmap -sV <ip>         detect the service/version on open ports
help · clear · reset

TASK CHECKLIST

Run a host-discovery sweep across 10.42.7.0/24.
Port-scan the catalog server 10.42.7.20.
Run service/version detection on 10.42.7.20.

QUESTIONS

1. How many hosts did your -sn sweep report as up on 10.42.7.0/24?

2. Which TCP port on lib-catalog01 carries encrypted (TLS) web traffic?

3. Port/socket numbers are addressed at which OSI layer?

4. lib-catalog01 has TCP/22 open. Which remote-administration protocol listens there?

Callsign / handle (no real names)

Score 0 / 7

Formative simulation. The answer key lives in this page, so the score is self-reported — for graded use, have the Apps Script re-score server-side. No real scanning occurs; nothing leaves your browser except your submission. © 2026 <author/org> — replace this notice before distribution.