Paths/DevOps Engineer/Networking / Ports & Sockets
Find What's Listening on Which Port
'Port 8080 is in use' is a daily incident. Use ss to list listening sockets, find the port the app process listens on and record it.
Validator
⏱ 0:00
IDLE — checks run live as you type commands; submit when done
01Requirements
live checks- Directory ~/report exists○
- File ~/report/app-port.txt exists and contains the app's listening port○
02Walkthrough
1 of 4 revealed- 01
List listening TCP sockets
ss -tlnp shows: t TCP sockets, l listening only, n numeric ports, p the owning process. Three services are listening on this machine.
ss -tlnp - 3 locked · each failed submit reveals one
03Stuck?
0 of 3 revealedTake a hint without losing the lab — each one points at the thing to look at, not at the answer.
04AI Tutor
guides, never solvesTell me what you're stuck on — I'll nudge, not solve. Which requirement are you looking at?
04Notebook
saved locally in this browserlearner@lab — ubuntu:24.04
Session is disposable
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