ifconfig Linux command

The ifconfig command in Linux is used to view and configure network interfaces, assign IP addresses, enable or disable network interfaces, and diagnose network connection issues. By running ifconfig with appropriate options, users can display a list of all network interfaces on the system along with their current configurations. This command is essential for monitoring network traffic, troubleshooting connectivity problems, and configuring network settings. It is a versatile tool that provides valuable information about network interfaces and plays a crucial role in managing network connections effectively.

ifconfig Syntax:

ifconfig [interface] [options]

Options:

Option	Description
-a	Display all interfaces
-s	Display a short summary
up	Activate the specified interface
down	Deactivate the specified interface
add	Add a new IPv4 address
del	Delete an IPv4 address
netmask	Specify the netmask for an interface

Parameters:

Parameter	Description
interface	Specifies the network interface to configure
options	Additional configuration options

Caution

Exercise caution when using the ifconfig command as it allows for direct manipulation of network interface configurations, which can impact network connectivity and system stability if not used carefully.

ifconfig bash Examples:

Display All Network Interfaces

ifconfig

Displays information about all network interfaces on the system.

Display Information for a Specific Interface

ifconfig eth0

Displays detailed information about the network interface “eth0”.

Enable a Network Interface

ifconfig eth0 up

Enables the network interface “eth0”.

Disable a Network Interface

ifconfig eth0 down

Disables the network interface “eth0”.

Assign an IP Address to an Interface

ifconfig eth0 192.168.1.100

Assigns the IP address “192.168.1.100” to the network interface “eth0”.

Change Netmask of an Interface

ifconfig eth0 netmask 255.255.255.0

Changes the netmask of the network interface “eth0” to “255.255.255.0”.

Tip

Remember to use the ifconfig command with caution, as it requires administrative privileges and can make changes to network configurations that may disrupt network connectivity if used incorrectly.

How do I use ifconfig in Linux?

To use the ifconfig command in Linux, execute the following command:

ifconfig

How to display only IPv4 addresses using ifconfig?

To display only IPv4 addresses using ifconfig, use the following command:

ifconfig | grep -oE "inet addr:[^ ]*" | grep -oE "[0-9.]*"

How to bring up a network interface using ifconfig?

To bring up a network interface using ifconfig, run the following command:

sudo ifconfig eth0 up

How to assign an IP address to a network interface using ifconfig?

To assign an IP address to a network interface using ifconfig, use the following command:

sudo ifconfig eth0 192.168.1.10 netmask 255.255.255.0

How to set a default gateway using ifconfig?

To set a default gateway using ifconfig, execute the following command:

sudo route add default gw 192.168.1.1

How to display detailed information about all network interfaces using ifconfig?

To display detailed information about all network interfaces using ifconfig, run the following command:

ifconfig -a

How to disable a network interface using ifconfig?

To disable a network interface using ifconfig, use the following command:

sudo ifconfig eth0 down

How to change the MAC address of a network interface using ifconfig?

To change the MAC address of a network interface using ifconfig, execute the following command:

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

Applications of the ifconfig command

• Configure network interfaces
• Display network interface information
• Enable or disable network interfaces
• Assign IP addresses to network interfaces
• View current network configuration
• Troubleshoot network connectivity issues