OSI Model Unwrapped! Troubleshoot by Layer

You'll learn

• Why you troubleshoot from the bottom: every floor depends on the floor beneath it, and a low fault wears every disguise above it
• Question 1, the link light (Layer 1): the lamp, the port, ipconfig "Media disconnected"
• Question 2, the neighbours (Layer 2): ping a machine on your own street, arp -a, and the replaced network card the allow-list doesn't know
• Question 3, the gateway (Layer 3): ping the gateway ipconfig names, not the one you assume — the .11 typo, and the rule with no exceptions
• Question 4, the door (Layer 4): why ping is a mail bag that never touches a door, and Test-NetConnection to test the door itself
• Question 5, the name (Layer 7): if the address works and the name doesn't, it's DNS — nslookup shows the shout and the silence
• The real names: bottom-up, top-down and divide-and-conquer, and what to look at when all five questions pass (the expired certificate, the 32-second call drop, a 404)
• The real thing: the five commands run in order on one ticket, stopping at the first failure, fixing it, and running the ladder again
• Exam corner: which troubleshooting approach starts at the physical layer

Chapters

1. 0:00Five tickets, four words
2. 0:29The reason the map exists
3. 1:19Question 1: is there a link light?
4. 1:43Question 2: can it see its neighbours?
5. 2:13Question 3: can it reach the gateway?
6. 2:52Question 4: is the door open? Ping is a mail bag
7. 3:42Question 5: does the name resolve?
8. 4:12Five tickets, five floors
9. 4:29The real names: bottom-up, top-down, divide and conquer
10. 5:00Two honest notes, and above the door
11. 5:38The real thing: five commands, one ticket
12. 6:55Exam corner
13. 7:16Recap, and the series closes