User:Lzhang45/sandbox

ifupdown (network interface manager) introduction

Ifupdown is a network interface manager for Linux. The ifupdown package provides a standardized framework for the high level network configuration.

Features

The tool configures network by setting configuration files to make this job simple and automatic. By editing system file "/etc/network/interfaces", users can easily change network configuration.

Ifupdown also provides useful softwares ifup and ifdown. They offer high level network configuration dictated by the configuration file "/etc/network/interfaces". Ifup is for bringing a network interface up and ifdown is for taking a network interface down.

Ifupdown can be used to set up various interfaces, such as

A basic way to configure network is, first edit file "/etc/network/interfaces", then use basic ifup/ifdown command to bring up or take down a interface.[2]

Basic syntax of file "/etc/network/interfaces"

• auto <interface_name>

Start interface <interface_name> upon start of the system.

• allow-
  hotplug
  <interface_name>

Start interface <interface_name> when the kernel detects a hotplug event from the interface.

• Lines started with "iface <config_name> ..."

Define the network configuration <config_name>.

• Lines started with "mapping <interface_name_glob>"

Define mapping value of <config_name> for the matching <interface_name>.

• A line starting with a hash "#"

Ignore as comments (end-of-line comments are not supported).

• A line ending with a backslash "\"

Extend the configuration to the next line.

Basic network configuration commands

• ifup <interface_name>

Bring up a network interface <interface_name> with the configuration <interface_name> if "iface <interface_name>" stanza exists in file "/etc/network/interfaces".

• ifup <interface_name>

Take down a network interface <interface_name> with the configuration <interface_name> if "iface <interface_name>" stanza exists in file "/etc/network/interfaces".

Basic Usage Example

Here is an example of file "/etc/network/interfaces" in Debian operating system.

auto lo
iface lo inet loopback

auto eth0
allow-hotplug eth0

iface eth0 inet6 auto

iface eth0 inet static
    address 45.79.155.57/24
    gateway 45.79.155.1

There are two interfaces configured in this example: eth0 interface and loopback network interface.

Updated Version

An updated version of ifupdown is Ifupdown2, which is for Cumulus Linux

• The lack of ability to handle interface dependencies.
• Incremental updates to interface configuration without disruption.
• Interface configuration validation.

See also

• network interface manager

References