ifdown(8) - phpMan

ifup(8) ifup(8)

NAME
ifup - bring a network interface up

ifdown - take a network interface down

SYNOPSIS
ifup [-nv] [--no-act] [--verbose] [-i FILE|--interfaces=FILE] [--allow CLASS] -a|IFACE...
ifup -h|--help
ifup -V|--version

ifdown [-nv] [--no-act] [--verbose] [-i FILE|--interfaces=FILE] [--allow CLASS]
-a|IFACE...

DESCRIPTION
The ifup and ifdown commands may be used to configure (or, respectively, deconfigure) net-
work interfaces based on interface definitions in the file /etc/network/interfaces.

OPTIONS
A summary of options is included below.

-a, --all
If given to ifup, affect all interfaces marked auto. Interfaces are brought up in
the order in which they are defined in /etc/network/interfaces. If given to
ifdown, affect all defined interfaces. Interfaces are brought down in the order in
which they are currently listed in the state file. Only interfaces defined in
/etc/network/interfaces will be brought down.

--force
Force configuration or deconfiguration of the interface.

-h, --help
Show summary of options.

--allow=CLASS
Only allow interfaces listed in an allow-CLASS line in /etc/network/interfaces to
be acted upon.

-i FILE, --interfaces=FILE
Read interface definitions from FILE instead of from /etc/network/interfaces.

-n, --no-act
Don't configure any interfaces or run any "up" or "down" commands.

--no-mappings
Don't run any mappings. See interfaces(5) for more information about the mapping
feature.

-V, --version
Show copyright and version information.

-v, --verbose
Show commands as they are executed.

EXAMPLES
ifup -a
Bring up all the interfaces defined with auto in /etc/network/interfaces

ifup eth0
Bring up interface eth0

ifup eth0=home
Bring up interface eth0 as logical interface home

ifdown -a
Bring down all interfaces that are currently up.

NOTES
ifup and ifdown are actually the same program called by different names.

The program does not configure network interfaces directly; it runs low level utilities
such as ifconfig and route to do its dirty work.

FILES
/etc/network/interfaces
definitions of network interfaces See interfaces(5) for more information.

/etc/network/run/ifstate
current state of network interfaces

KNOWN BUGS/LIMITATIONS
The program keeps records of whether network interfaces are up or down. Under exceptional
circumstances these records can become inconsistent with the real states of the inter-
faces. For example, an interface that was brought up using ifup and later deconfigured
using ifconfig will still be recorded as up. To fix this you can use the --force option
to force ifup or ifdown to run configuration or deconfiguration commands despite what it
considers the current state of the interface to be.

The file /etc/network/run/ifstate must be writable for ifup or ifdown to work properly.
If that location is not writable (for example, because the root filesystem is mounted
read-only for system recovery) then /etc/network/run/ifstate should be made a symbolic
link to a writable location. If that is not possible then you can use the --force option
to run configuration or deconfiguration commands without updating the file.

Note that the program does not run automatically: ifup alone does not bring up interfaces
that appear as a result of hardware being installed and ifdown alone does not bring down
interfaces that disappear as a result of hardware being removed. To automate the configu-
ration of network interfaces you need to install other packages such as hotplug(8) or
ifplugd(8).

AUTHOR
The ifupdown suite was written by Anthony Towns <aj AT azure.au>.