Provided by: ifupdown_0.7~beta2ubuntu8_amd64 bug

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/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.

       -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.

       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.  On
       Ubuntu the /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
       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 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).