ifconfig command
Detailed Explanation
ifconfig (interface configuration) is a legacy command-line utility used for network interface configuration, tuning, and debugging in Unix-like operating systems. It has been officially deprecated in most modern Linux distributions in favor of the ip command, but it is still widely recognized.
Basic Syntax
ifconfig [interface]
ifconfig interface [options] [address]
Common Flags/Options
| Option | Description |
|---|---|
-a | Display all interfaces, including those that are down. |
up | Activate the specified network interface. |
down | Deactivate the specified network interface. |
promisc | Enable promiscuous mode on the interface. |
netmask <addr> | Set the IP network mask for the interface. |
Real-world Examples
Display information for all active interfaces:
ifconfig
Display information for a specific interface:
ifconfig eth0
Bring an interface down:
sudo ifconfig eth0 down
Bring an interface up:
sudo ifconfig eth0 up
Assign an IP address and netmask:
sudo ifconfig eth0 192.168.1.100 netmask 255.255.255.0