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) network 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/net-
	      work/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.

       -e PATTERN, --exclude=PATTERN
	      Exclude interfaces from the list of interfaces to operate on by the PATTERN.  Notice that the PATTERN can be a full  interface  name
	      or substrings that match interfaces. Users could easily have unexpected behaviour if they use a small string to do the match.

       -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 ip to do its dirty work.

FILES

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

       /var/run/network/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 inconsis-
       tent with the real states of the interfaces.  For example, an interface that was brought up using ifup and later deconfigured using  ifcon-
       fig  will still be recorded as up.  To fix this you can use the --force option to force ifup or ifdown to run configuration or deconfigura-
       tion commands despite what it considers the current state of the interface to be.

       The file /var/run/network/ifstate must be writable for ifup or ifdown to work properly.	On Ubuntu the /var/run	location  is  a  temporary
       filesystem  which is always writable and thrown away on shutdown.  You can also use the --force option to run configuration or deconfigura-
       tion 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 configura-
       tion 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@azure.humbug.org.au>.

SEE ALSO

       interfaces(5), ip(8), ifconfig(8).

IFUPDOWN
							    22 May 2004 							   ifup(8)