Study and Use of ifconfig Command

 

 Experiment

 Study and Use of ifconfig Command

🎯 Aim

To familiarize students with the ifconfig command in Linux for viewing and configuring network interfaces.

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📘 Objective

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

• Display network interface details
• Enable/disable network interfaces
• Assign IP addresses manually
• Understand key networking parameters

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🧰 Prerequisites

• Linux system (e.g., Ubuntu/Debian/Kali)
• Basic terminal knowledge
• Root or sudo privileges

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📖 Theory

The ifconfig (interface configuration) command is used to:

• View network interface configuration
• Assign IP addresses
• Enable or disable interfaces

⚠️ Note: On modern systems, ifconfig is deprecated and replaced by the ip command (from iproute2), but it is still widely used for learning and legacy systems.

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🧾 Syntax

ifconfig [interface] [options]

• interface → Network interface name (e.g., eth0, wlan0)
• options → Actions like up, down, assigning IP, etc.

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🔬 Procedure & Commands

1️⃣ Display All Network Interfaces

ifconfig

👉 Shows:

• Interface names
• IP address
• MAC address
• Packet statistics

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2️⃣ Display Specific Interface

ifconfig eth0

👉 Replace eth0 with your interface name.

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3️⃣ Enable a Network Interface

sudo ifconfig eth0 up

👉 Activates the interface.

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4️⃣ Disable a Network Interface

sudo ifconfig eth0 down

👉 Deactivates the interface.

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5️⃣ Assign an IP Address

sudo ifconfig eth0 192.168.1.10

👉 Assigns a static IP.

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6️⃣ Assign IP with Netmask

sudo ifconfig eth0 192.168.1.10 netmask 255.255.255.0

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7️⃣ Change MAC Address

sudo ifconfig eth0 hw ether 00:11:22:33:44:55

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8️⃣ Check Packet Statistics

ifconfig eth0

👉 Look for:

• RX packets (received)
• TX packets (transmitted)

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📊 Sample Output (Important Fields Explained)

• inet → IP address
• netmask → Subnet mask
• broadcast → Broadcast address
• ether → MAC address
• RX/TX → Data packets

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📝 Exercises for Students

1. List all network interfaces on your system.
2. Identify your system’s IP address.
3. Disable and re-enable a network interface.
4. Assign a temporary IP address and verify it.
5. Observe packet count changes after browsing the web.

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❓ Viva Questions

• What is the purpose of ifconfig?
• Difference between ifconfig and ip command?
• What is a MAC address?
• What happens when an interface is brought down?

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⚠️ Precautions

• Use sudo carefully to avoid misconfiguration
• Do not change IP settings on production systems
• Always verify interface name before executing commands

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✅ Result

The ifconfig command helps in managing and monitoring network interfaces. It is a fundamental tool for understanding Linux networking basics.