Installer Wireshark localement

Lab

En bref

Un lab pratique sur votre propre machine : installez Wireshark et observez de vrais paquets — la poignée de main et les en-têtes appris — sur votre connexion.

Objectifs

Installer Wireshark localement
Capturer et filtrer le trafic en direct
Trouver une vraie poignée de main TCP dans votre capture

Everything so far has been theory. Now you will see it for real. Wireshark captures the packets crossing your own machine and shows you exactly what you have been reading about — the handshake, the headers, the layers.

Legal

Only ever capture traffic on a network you own or are authorised to monitor. Capturing on a network you do not control may be an offence under Algerian Law 09-04. On your own machine, on your own connection, you are fine.

Install and capture

Install Wireshark from your package manager or wireshark.org.
Open it and pick your active interface (usually wlan0 or eth0).
Type tcp.port == 443 in the filter bar and press Enter.
Open a website in your browser and watch the packets appear.

$ sudo apt install wireshark
Setting up wireshark ...
Do you want non-superusers to capture packets? Yes

Tip

You should see a SYN, a SYN-ACK and an ACK at the very start of each new connection. Find one. That is the handshake from the last section, live on your screen.

À retenir

Wireshark montre les paquets qui traversent votre machine
Ne capturez que sur des réseaux autorisés
La théorie devient réelle en voyant la poignée de main en direct