🛠 Configurer Ethernet et se connecter en SSH

Objectives

Install and use the Raspberry Pi 5 without a screen (headless): enable the SSH server, retrieve the IP address on the Gigabit local network, and connect from another computer. The Pi 5 features a Gigabit Ethernet controller (integrated MAC, driven by the RP1 chip), with PoE+ possible via a dedicated HAT.

Hardware

• Raspberry Pi 5 with official 27 W power supply (5 V / 5 A)
• microSD card with Raspberry Pi OS 64-bit (written with Raspberry Pi Imager)
• RJ45 Ethernet cable to a box/router
• A client computer (Linux, macOS, or Windows with OpenSSH)

Complete code

# 1) Préparer la carte : dans Raspberry Pi Imager, menu Options (Ctrl+Maj+X),
#    cocher « Activer SSH » (utilisateur + clé) et le Wi-Fi si besoin.
#    Alternative manuelle après écriture :
sudo touch /boot/firmware/ssh    # active sshd au premier démarrage (Bookworm)

# 2) Démarrer, brancher le câble, puis trouver l'adresse IP depuis le Pi :
ip -4 addr show eth0 | grep inet
#    ou sans écran, depuis le réseau :
arp -a | grep b8:27:eb          # préfixe MAC courant de Raspberry Pi
ping -c3 raspberrypi.local       # découverte par mDNS

# 3) Depuis le poste client :
ssh utilisateur@raspberrypi.local

# 4) Sur le Pi : sécuriser et fixer l'identité
sudo hostnamectl set-hostname labo-pi5
sudo apt update && sudo apt upgrade -y
sudo systemctl enable --now ssh

# 5) Débit Ethernet réel (test iperf3 contre une machine du réseau)
sudo apt install -y iperf3
iperf3 -c 192.168.1.10

Expected verification

ssh user@raspberrypi.local opens a remote session; the prompt displays the new hostname. iperf3 approaches 940 Mbit/s on a healthy Gigabit network. systemctl is-enabled ssh returns enabled.

Common errors

• Forgetting to enable SSH when writing the image: connection refused; rewrite the image or create the ssh file in the boot partition.
• Looking for raspberrypi.local without an mDNS service on Windows: install Bonjour or use the raw IP.
• Undersized power supply: with a power supply other than 5 V/5 A, the USB budget is limited to 600 mA and network drops may occur under load.
• SSH key permissions incorrect: chmod 700 ~/.ssh && chmod 600 ~/.ssh/authorized_keys.
• Confusing eth0 and wlan0: check the active interface with ip link before reading the IP.