ifquery


       ifdown - take a network interface down

       ifquery - parse interface configuration

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...

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

       ifquery  -l|--list  [-nv]  [--no-act]  [--verbose]  [-i   FILE|--inter-
       faces=FILE] [--allow CLASS] -a|IFACE...

       ifquery --state [IFACE...]

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

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

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

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

       --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 inter-
              face is configured just once anyway. If, however, another inter-
              face  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 inter-
              faces 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/net-
              work/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,  ifdown, and ifquery are actually the same program called by dif-
       ferent 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.

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

       /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  inconsistent
       with the real states of the interfaces.  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  /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 interfaces 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).

AUTHOR
       The  ifupdown  suite  was  written  by  Anthony  Towns   <aj@azure.hum-
       bug.org.au>.

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



IFUPDOWN                          22 May 2004                          ifup(8)
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