ifconfig

Linux · Network · reference only

What it does

Shows and configures network interfaces with the classic syntax. It is obsolete compared with ip, but still appears in many manuals.

Syntax

ifconfig [interfaz] [opciones]

Options and parameters

• -a

  Shows all interfaces, including the ones that are down.

• -s

  Shows a short table with per-interface statistics.

• up

  Brings the interface up.

• down

  Brings the interface down.

• netmask máscara

  Sets the netmask.

• mtu N

  Changes the maximum packet size.

Usage examples

• ifconfig

  Shows the active interfaces with their IP address.

• ifconfig eth0

  Shows only the data of the eth0 interface.

• sudo ifconfig eth0 down

  Turns the eth0 interface off.

• sudo ifconfig eth0 192.168.1.50 netmask 255.255.255.0

  Assigns an address and a netmask to eth0 temporarily.

Notes and common mistakes

• It ships in the net-tools package, which is not installed by default on Debian 12: sudo apt install net-tools.
• The modern equivalent is ip addr; changes made with ifconfig do not survive a reboot.

Related commands

• curl
• dig
• dnsdomainname
• hostname
• ip
• netstat