ifconfig and ip addr in Linux CLI - Step-by-Step Execution

Concept Flow - ifconfig and ip addr

Start

↓

Run ifconfig

↓

Display network interfaces and details

↓

Run ip addr

↓

Display network interfaces with IP info

↓

Compare outputs

↓

End

The flow shows running 'ifconfig' and 'ip addr' commands to display network interface details and IP addresses, then comparing their outputs.

Execution Sample

Linux CLI

ifconfig
ip addr

Runs 'ifconfig' and 'ip addr' commands to show network interfaces and their IP addresses.

Execution Table

Step	Command	Action	Output Summary
1	ifconfig	Runs ifconfig to list interfaces	Shows interfaces with IP, MAC, RX/TX stats
2	ip addr	Runs ip addr to list interfaces	Shows interfaces with IP addresses and states
3	Compare	Look at differences	ip addr shows more detailed info and modern format
4	Exit	Commands finished	No more output

💡 Both commands finish after displaying network interface information.

Variable Tracker

Variable	Start	After ifconfig	After ip addr	Final
interfaces_list	empty	list of interfaces with IP and MAC	list of interfaces with IP, MAC, state	final detailed interface info

Key Moments - 2 Insights

Why does 'ip addr' show more details than 'ifconfig'?

'ip addr' is a newer tool that shows more info like interface state and supports modern Linux networking features, as seen in execution_table step 2.

Are 'ifconfig' and 'ip addr' interchangeable?

'ifconfig' is older and may not be installed by default; 'ip addr' is recommended for modern systems, shown by their different outputs in execution_table steps 1 and 2.

Visual Quiz - 3 Questions

Look at the execution table, what does the 'ifconfig' command output mainly show?

A Network interfaces with IP, MAC, and RX/TX stats

B Only IP addresses

C Routing table

D Firewall rules

💡 Hint

See execution_table row 1 under Output Summary

At which step does the output show interface states like UP or DOWN?

A Step 1

B Step 3

C Step 2

D Step 4

💡 Hint

Check execution_table row 2 Action and Output Summary

If 'ifconfig' is not installed, which command should you use to see IP addresses?

A ping

B ip addr

C netstat

D traceroute

💡 Hint

Refer to key_moments about modern tool recommendation

Concept Snapshot

ifconfig and ip addr show network interfaces.
ifconfig is older, shows IP, MAC, RX/TX stats.
ip addr is newer, shows IP, MAC, interface state.
Use ip addr on modern Linux systems.
Both commands display interface info but differ in detail.

Full Transcript

This lesson shows how to use 'ifconfig' and 'ip addr' commands in Linux to view network interfaces and their IP addresses. First, running 'ifconfig' lists interfaces with IP addresses, MAC addresses, and data statistics. Then, running 'ip addr' shows interfaces with IP addresses and their states like UP or DOWN. 'ip addr' is a newer tool with more detailed output and is recommended on modern systems. The execution table traces these steps and outputs. Key moments clarify why 'ip addr' shows more info and when to use each command. The visual quiz tests understanding of command outputs and usage. The concept snapshot summarizes the main points for quick reference.

Practice

1. What is the main purpose of the ifconfig and ip addr commands in Linux?

easy

A. To manage user accounts

B. To edit text files in the system

C. To monitor CPU usage

D. To display network interface details and IP addresses

Solution

1. Step 1: Understand command purpose

   The commands ifconfig and ip addr are used to show details about network interfaces and their IP addresses.

2. Step 2: Eliminate unrelated options

   Options about editing files, managing users, or CPU monitoring do not relate to network interfaces.

3. Final Answer:

   To display network interface details and IP addresses -> Option D

4. Quick Check:

   Network info = C [OK]

Hint: Remember: both commands show network info, not files or users [OK]

Common Mistakes:

• Confusing network commands with file editing tools
• Thinking these commands manage users
• Assuming they monitor CPU or memory

2. Which of the following is the correct syntax to display all IP addresses using the ip command?

easy

A. ip address list all

B. ip show addr

C. ip addr show

D. ip display ip

Solution

1. Step 1: Recall correct command syntax

   The correct syntax to show IP addresses is ip addr show or simply ip addr.

2. Step 2: Check other options for errors

   Options B, C, and D use incorrect order or invalid keywords.

3. Final Answer:

   ip addr show -> Option C

4. Quick Check:

   Correct syntax = A [OK]

Hint: Remember: 'ip addr show' is the standard order [OK]

Common Mistakes:

• Swapping 'addr' and 'show' order
• Using invalid keywords like 'display' or 'list all'
• Adding unnecessary words

3. What will be the output of the command ifconfig eth0 if the interface eth0 is up with IP 192.168.1.10 and netmask 255.255.255.0?

medium

A. Shows interface eth0 details including IP 192.168.1.10 and netmask 255.255.255.0

B. Shows only the MAC address of eth0

C. Shows error: interface eth0 not found

D. Shows CPU usage statistics

Solution

1. Step 1: Understand ifconfig eth0 output

   This command displays detailed info about the eth0 interface, including IP address and netmask if the interface is up.

2. Step 2: Eliminate unrelated outputs

   It does not show only MAC address, CPU stats, or error if interface exists and is up.

3. Final Answer:

   Shows interface eth0 details including IP 192.168.1.10 and netmask 255.255.255.0 -> Option A

4. Quick Check:

   ifconfig eth0 shows IP and netmask = D [OK]

Hint: ifconfig with interface name shows full details [OK]

Common Mistakes:

• Expecting only MAC address output
• Assuming error if interface is active
• Confusing with CPU or system stats

4. You run ip addr show eth0 but get no output. What is the most likely reason?

medium

A. The eth0 interface does not exist or is down

B. You need to run the command as root

C. The command syntax is incorrect

D. The IP address is not assigned yet

Solution

1. Step 1: Analyze command behavior

   If ip addr show eth0 returns no output, it usually means the interface eth0 does not exist or is disabled.

2. Step 2: Check other options

   Running as root is not required to show interfaces; syntax is correct; lack of IP alone does not cause no output.

3. Final Answer:

   The eth0 interface does not exist or is down -> Option A

4. Quick Check:

   No output means interface missing/down = B [OK]

Hint: No output usually means interface missing or down [OK]

Common Mistakes:

• Assuming root is needed to view interfaces
• Thinking syntax is wrong
• Confusing no IP with no output

5. You want to write a script that checks if the interface eth1 has an IP address assigned using ip addr. Which command snippet correctly tests this?

hard

A. ifconfig eth1 | grep -q 'inet6 '; then echo 'IP assigned'; else echo 'No IP'; fi

B. if ip addr show eth1 | grep -q 'inet '; then echo 'IP assigned'; else echo 'No IP'; fi

C. ip addr show eth1 | grep -q 'ether '; then echo 'IP assigned'; else echo 'No IP'; fi

D. if ip link show eth1 | grep -q 'UP'; then echo 'IP assigned'; else echo 'No IP'; fi

Solution

1. Step 1: Identify correct IP address check

   The command ip addr show eth1 lists addresses; searching for 'inet ' finds IPv4 addresses assigned.

2. Step 2: Evaluate other options

   ifconfig eth1 | grep -q 'inet6 '; then echo 'IP assigned'; else echo 'No IP'; fi checks IPv6 with ifconfig but question asks for ip addr. ip addr show eth1 | grep -q 'ether '; then echo 'IP assigned'; else echo 'No IP'; fi looks for MAC address ('ether'), not IP. if ip link show eth1 | grep -q 'UP'; then echo 'IP assigned'; else echo 'No IP'; fi checks interface status, not IP assignment.

3. Final Answer:

   if ip addr show eth1 | grep -q 'inet '; then echo 'IP assigned'; else echo 'No IP'; fi -> Option B

4. Quick Check:

   Check 'inet ' in ip addr output = A [OK]

Hint: Search 'inet ' in ip addr output to find IPv4 address [OK]

Common Mistakes:

• Checking MAC address instead of IP
• Using ip link instead of ip addr
• Confusing IPv6 with IPv4 check