ifdown(8) - man - phpMan

ifup(8)                                                                                      ifup(8)



NAME
       ifup - bring a network interface up

       ifdown - take a network interface down

       ifquery - parse interface configuration

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

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

       ifquery  [-nv]  [--verbose]  [-i  FILE|--interfaces=FILE]  [--state-dir=DIR]  [--allow CLASS]
       IFACE...

       ifquery -l|--list [-nv] [--verbose] [-i  FILE|--interfaces=FILE]  [--state-dir=DIR]  [--allow
       CLASS] [-a|IFACE...]

       ifquery --state [--state-dir=DIR] [--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.  ifquery  com‐
       mand may be used to parse interfaces configuration.

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.   Combined  with  --allow,
              acts  on  all interfaces of a specified class instead.  If given to ifdown, affect all
              defined interfaces.  Interfaces are brought down in the order in which they  are  cur‐
              rently  listed  in  the state file. Only interfaces defined in /etc/network/interfaces
              will be brought down.

       --force
              Force configuration or deconfiguration of the interface.

       --ignore-errors
              If any of the commands of scripts fails, continue.

       -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.

       --state-dir=DIR
              Keep interface state in DIR instead of in /run/network.

       -X PATTERN, --exclude=PATTERN
              Exclude  interfaces from the list of interfaces to operate on by the PATTERN.  PATTERN
              uses a usual shell glob syntax. If shell wildcards are not used, it must match the ex‐
              act interface name. This option may be specified multiple times resulting in more than
              one pattern being excluded.

       -o OPTION=VALUE
              Set OPTION to VALUE as though it were in /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 fea‐
              ture.

       --no-scripts
              Don't run any scripts under /etc/network/if-*.d/

       --no-loopback
              Disable special handling of the loopback interface. By default, the loopback interface
              (lo on Linux) is predefined internally as an auto interface, so  it's  brought  up  on
              ifup  -a  automatically. In the case the loopback device is redefined by user, the in‐
              terface is configured just once anyway. If, however, another interface is also defined
              as loopback, it's configured as usual. Specifying this option disables this behaviour,
              so the loopback interface won't be configured automatically.

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

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

       -l, --list
              For ifquery, list all the interfaces which match the specified  class.   If  no  class
              specified, prints all the interfaces listed as auto.

       --state
              For ifquery, dump the state of the interfaces. When no interfaces specified, lists all
              interfaces brought up together with logical interfaces assigned to them and exits with
              a  status  code indicating success. If one or more interfaces specified, display state
              of these interfaces only; successful code is returned if all of  interfaces  given  as
              arguments are up. Otherwise, 0 is returned.

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.

       ifquery -l
              Print names of all interfaces specified with the auto keyword.

       ifquery -l --allow=hotplug
              Print names of all interfaces specified with the allow-hotplug keyword.

       ifquery eth0
              Display  the  interface  options as specified in the ifupdown configuration. Each key-
              value pair is printed out on individual line using ": " as separator.

NOTES
       ifup, ifdown, and ifquery 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.

       When invoked, ifdown checks if ifup is still running. In that case, SIGTERM is sent to ifup.

       During  interface  deconfiguration,  ifdown ignores errors the same way as if --ignore-errors
       was specified.

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

       /run/network/ifstate
              current state of network interfaces

CONCURRENCY
       Ifupdown uses per-interface locking to ensure that concurrent ifup and ifdown  calls  to  the
       same interface are run in serial.  However, calls to different interfaces will be able to run
       in parallel.

EXIT STATUS
       For ifup and ifdown, the exit status will be 0  if  the  given  interface(s)  have  all  been
       (de)configured successfully, 1 if there was any error.  The result of these commands is idem‐
       potent; running ifup on an interface that is already up will result in an exit status  of  0,
       and  similarly running ifdown on an interface that is not up will also result in an exit sta‐
       tus of 0.

       ifquery will normally return with exit status 0 if an interface with a matching iface stanza,
       1 if there is no matching stanza.  ifquery --state will also return with exit status 1 if the
       given interface was known but was not up.

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 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 deconfiguration commands despite what it considers the cur‐
       rent state of the interface to be.

       The  file /run/network/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 /run/network/ifstate should be made a symbolic link to a writable loca‐
       tion.  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  in‐
       terfaces that disappear as a result of hardware being removed.  To automate the configuration
       of network interfaces you need to install other packages such as udev(7) or ifplugd(8).

AUTHORS
       The ifupdown suite was created by Anthony  Towns  <aj AT azure.au>,  currently  main‐
       tained by Santiago Ruano Rincón <santiago AT debian.org> and Josue Ortega <josue AT debian.org>

       Many others have helped develop ifupdown over time, see /usr/share/doc/ifupdown/changelog.De‐
       bian.gz for a full history.

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



IFUPDOWN                                     11 Jan 2017                                     ifup(8)