Network Manager CLI Cheat Sheet

Introduction

I’m writing this as a reference for myself, I had to do some nmcli work recently so wanted a quick reference guide in case I have to do it again.

Overview:
- NetworkManager is a service for managing network connections on Linux systems. This cheat sheet covers essential nmcli commands for common networking tasks.
- While graphical tools exist, nmcli provides more control and is essential for server environments or automation scripts.
- Many operations require root privileges (sudo), especially those that modify system network settings.

Basic Commands

General Status

# Show overall network status
nmcli general status

# Show detailed status of all devices
nmcli device status

WiFi Operations:

# List available WiFi networks
nmcli device wifi list

# Connect to a WiFi network
nmcli device wifi connect [SSID] password ["yourpassword"]

# Connect to a hidden WiFi network
nmcli device wifi connect [SSID] password ["yourpassword"] hidden yes

# Turn WiFi on/off
nmcli radio wifi on
nmcli radio wifi off

Connection Management:

# List all connections
nmcli connection show

# Show active connections
nmcli connection show --active

# Show detailed information about a specific connection
nmcli connection show "connection_name"

# Delete a connection
nmcli connection delete "connection_name"

# Modify connection properties
nmcli connection modify "connection_name" ipv4.addresses "192.168.1.100/24"
nmcli connection modify "connection_name" ipv4.gateway "192.168.1.1"
nmcli connection modify "connection_name" ipv4.dns "8.8.8.8"

Advanced Operations:

Creating New Connections:

# Create a new WiFi connection
nmcli connection add type wifi con-name "MyWiFi" ifname wlan0 ssid "NetworkName"

# Create a static IP connection
nmcli connection add type ethernet con-name "Static" ifname eth0 \
    ipv4.addresses 192.168.1.100/24 ipv4.gateway 192.168.1.1 \
    ipv4.dns "8.8.8.8,8.8.4.4" ipv4.method manual

Troubleshooting:

# Restart a connection
nmcli connection down "connection_name"
nmcli connection up "connection_name"

# Reset all network settings
nmcli networking off
nmcli networking on

# Show detailed device information
nmcli device show

# Monitor network changes
nmcli monitor

Security Operations:

# Show stored WiFi passwords
nmcli -show-secrets connection show "connection_name"

# Change WiFi password
nmcli connection modify "connection_name" wifi-sec.psk "new_password"

Common Error Messages

# Error: "Device not found"
# Solution: Check if the device exists and is recognized
nmcli device status
ip link show

# Error: "Connection activation failed: (7) Secrets were required, but not provided"
# Solution: Ensure the password is correct and properly quoted
nmcli device wifi connect "SSID" password "correct_password"

# Error: "Connection activation failed: (2) Active connection removed before it was initialized"
# Solution: Often indicates driver issues. Try reloading the WiFi driver:
sudo modprobe -r wifi_driver_name  # Replace with your actual driver
sudo modprobe wifi_driver_name

Tips

Use tab completion with nmcli for easier command typing
Connection names are case-sensitive
Use quotes around SSIDs or connection names that contain spaces (you can escape using \ e.g Super\ Secure\ SSID)
Most system-wide network changes require root privileges (sudo)
Always backup your network configuration before making significant changes
Use nmcli monitor to troubleshoot connection issues in real-time