Study of nmcli Command

 

Experiment

Study of nmcli Command

🎯 Aim

To configure and manage network connections using the nmcli command in Linux.

📘 Objective

By the end of this experiment, students will be able to:

  • View network devices and connections
  • Connect to wired and wireless networks
  • Configure IP settings
  • Manage network profiles using CLI

📖 Theory

The nmcli (Network Manager Command Line Interface) is used to:

  • Control the NetworkManager service from the terminal
  • Manage network connections (wired, Wi-Fi, VPN)
  • Configure IP addresses, DNS, and gateways

👉 It is a modern and powerful alternative to manual configuration using ifconfig or ip.

👉 It works with:

  • Devices (hardware interfaces)
  • Connections (saved network profiles)

🧾 Syntax

nmcli [OPTIONS] OBJECT COMMAND

Common OBJECTS:

  • device → Network interfaces
  • connection → Network profiles
  • general → NetworkManager status

🧰 Prerequisites

  • Linux system with NetworkManager
  • Root/sudo privileges for configuration

🔬 Procedure & Commands

1️⃣ Check NetworkManager Status

nmcli general status

2️⃣ List Network Devices

nmcli device status

3️⃣ Show All Connections

nmcli connection show

4️⃣ Display Device Details

nmcli device show

5️⃣ Connect to a Wi-Fi Network

nmcli device wifi connect "SSID_NAME" password "PASSWORD"

6️⃣ List Available Wi-Fi Networks

nmcli device wifi list

7️⃣ Bring Up a Connection

nmcli connection up "connection_name"

8️⃣ Bring Down a Connection

nmcli connection down "connection_name"

9️⃣ Add a New Connection (Static IP)

nmcli connection add type ethernet ifname eth0 con-name mynet ip4 192.168.1.10/24 gw4 192.168.1.1

🔟 Modify Connection Settings

nmcli connection modify mynet ipv4.dns "8.8.8.8"

🖥️ Sample Output

DEVICE      TYPE          STATE          CONNECTION
eth0        ethernet      connected      Wired connection 1
wlan0       wifi          disconnected     --

🔍 Output Interpretation

FieldMeaning
DEVICE            Interface name
TYPE            Network type (ethernet/wifi)
STATE            Current status
CONNECTION            Active connection profile

📝 Exercises for Students

  1. List all network devices and identify their status.
  2. Display saved network connections.
  3. Connect to a Wi-Fi network using nmcli.
  4. Create a new connection with static IP.
  5. Bring a connection down and up again.

❓ Viva Questions

  • What is nmcli?
  • Difference between device and connection?
  • What is NetworkManager?
  • How does nmcli differ from ip command?
  • Why is nmcli useful in servers?

⚠️ Precautions

  • Requires root privileges for configuration
  • Incorrect settings may disconnect network
  • Ensure correct interface and connection names

✅ Result

The nmcli command is a powerful CLI tool for managing network configurations efficiently, especially in systems without a graphical interface.

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