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Recap - Layer Four

Lesson 20 of 32 in Coddy's The OSI Model course.

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Challenge

Easy

Every service has a home port. Print the default port for each protocol, one per line, in this order:

  1. HTTP
  2. HTTPS
  3. DNS

Expected output:

80
443
53

Try it yourself

Terminal

All lessons in The OSI Model

1Why Layers

The Layering IdeaSeven LayersNumbers and NamesRecap - The Stack

4The Network Layer

IP and TTLPing and ICMPRouting TablesRecap - Layer Three

7Encapsulation

Wrapping DataHeaders EverywhereReading a CaptureRecap - Follow the Wrap

2The Physical Layer

Bits on a WireHow Long Will It TakeDuplex and Collisions

5Transport: TCP and UDP

PortsThe TCP HandshakeTCP vs UDPSockets in ActionRecap - Layer Four

8The Journey of a Packet

A Click HappensCrossing the NetworksArriving and ClimbingRecap - End to End

3Data Link and MACs

Frames and MACsReading a MACARPRecap - Layer Two

6The Upper Layers

Session and PresentationThe Application LayerWatching the LayersRecap - Top of the Stack

Practice on your own: Terminal playground