Provided by: ifupdown_0.7~beta2ubuntu8_i386 bug

NAME

       /etc/network/interfaces  - network interface configuration for ifup and
       ifdown

DESCRIPTION

       /etc/network/interfaces  contains   network   interface   configuration
       information  for the ifup(8) and ifdown(8) commands.  This is where you
       configure how your system is connected to the network.

       Lines starting with `#' are ignored. Note that end-of-line comments are
       NOT supported, comments must be on a line of their own.

       A  line  may  be  extended  across  multiple  lines  by making the last
       character a backslash.

       The file consists of zero or more "iface", "mapping", "auto",  "allow-"
       and "source" stanzas. Here is an example.
       auto lo eth0
       allow-hotplug eth1

       iface lo inet loopback

       source interfaces.d/machine-dependent

       mapping eth0
            script /usr/local/sbin/map-scheme
            map HOME eth0-home
            map WORK eth0-work

       iface eth0-home inet static
            address 192.168.1.1
            netmask 255.255.255.0
            up flush-mail

       iface eth0-work inet dhcp

       iface eth1 inet dhcp
       Lines  beginning with the word "auto" are used to identify the physical
       interfaces to be brought up when ifup is run with the -a option.  (This
       option  is  used by the system boot scripts.)  Physical interface names
       should follow the word "auto" on the same line.  There can be  multiple
       "auto"  stanzas.   ifup  brings  the  named  interfaces up in the order
       listed.

       Lines beginning with "allow-" are  used  to  identify  interfaces  that
       should  be  brought  up automatically by various subsytems. This may be
       done using a command such as "ifup --allow=hotplug  eth0  eth1",  which
       will  only  bring up eth0 or eth1 if it is listed in an "allow-hotplug"
       line. Note that "allow-auto" and "auto" are synonyms.

       Lines beginning with "source" are used to include  stanzas  from  other
       files, so configuration can be split into many files. The word "source"
       is followed by the path of file to be sourced. Shell wildcards  can  be
       used.  (See wordexp(3) for details.)

       Stanzas  beginning  with the word "mapping" are used to determine how a
       logical interface name is chosen for a physical interface that is to be
       brought  up.   The  first line of a mapping stanza consists of the word
       "mapping" followed by a pattern in shell  glob  syntax.   Each  mapping
       stanza  must contain a script definition.  The named script is run with
       the physical interface name as its argument and with  the  contents  of
       all  following  "map"  lines  (without the leading "map") in the stanza
       provided to it on its standard input. The script must print a string on
       its        standard        output       before       exiting.       See
       /usr/share/doc/ifupdown/examples for examples of what the  script  must
       print.

       Mapping a name consists of searching the remaining mapping patterns and
       running the script corresponding to the first match; the script outputs
       the name to which the original is mapped.

       ifup  is  normally  given  a  physical  interface  name  as  its  first
       non-option argument.  ifup also uses this name as the  initial  logical
       name  for  the  interface  unless it is accompanied by a  suffix of the
       form =LOGICAL, in which  case  ifup  chooses  LOGICAL  as  the  initial
       logical  name for the interface.  It then maps this name, possibly more
       than once according to successive  mapping  specifications,   until  no
       further  mappings  are  possible.  If the resulting name is the name of
       some defined logical interface then  ifup  attempts  to  bring  up  the
       physical  interface  as  that  logical interface.  Otherwise ifup exits
       with an error.

       Stanzas defining logical interfaces start with a line consisting of the
       word  "iface" followed by the name of the logical interface.  In simple
       configurations without mapping stanzas this name should simply  be  the
       name  of  the  physical  interface  to which it is to be applied.  (The
       default mapping script is, in effect, the echo command.)  The interface
       name  is  followed by the name of the address family that the interface
       uses.  This will be "inet" for TCP/IP networking,  but  there  is  also
       some support for IPX networking ("ipx"), and IPv6 networking ("inet6").
       Following that is  the  name  of  the  method  used  to  configure  the
       interface.

       Additional  options  can  be  given  on subsequent lines in the stanza.
       Which options are available  depends  on  the  family  and  method,  as
       described  below.   Additional  options  can be made available by other
       Debian  packages.   For  example,  the  wireless-tools  package   makes
       available  a  number  of options prefixed with "wireless-" which can be
       used to configure the interface using  iwconfig(8).   (See  wireless(7)
       for details.)

       Options  are usually indented for clarity (as in the example above) but
       are not required to be.

IFACE OPTIONS

       The following "command" options are  available  for  every  family  and
       method.   Each of these options can be given multiple times in a single
       stanza, in which case the commands are executed in the order  in  which
       they  appear  in  the stanza.  (You can ensure a command never fails by
       suffixing "|| true".)

       pre-up command
              Run command before bringing the interface up.  If  this  command
              fails then ifup aborts, refraining from marking the interface as
              configured, prints an error message, and exits  with  status  0.
              This behavior may change in the future.

       up command

       post-up command
              Run  command  after  bringing the interface up.  If this command
              fails then ifup aborts, refraining from marking the interface as
              configured  (even  though it has really been configured), prints
              an error message, and exits with status 0.   This  behavior  may
              change in the future.

       down command

       pre-down command
              Run  command  before taking the interface down.  If this command
              fails then ifdown aborts, marks the  interface  as  deconfigured
              (even  though  it  has  not really been deconfigured), and exits
              with status 0.  This behavior may change in the future.

       post-down command
              Run command after taking the interface down.   If  this  command
              fails  then  ifdown aborts, marks the interface as deconfigured,
              and exits with status  0.   This  behavior  may  change  in  the
              future.

       There  exists  for  each  of  the  above  mentioned options a directory
       /etc/network/if-<option>.d/ the scripts  in  which  are  run  (with  no
       arguments)   using  run-parts(8)  after  the  option  itself  has  been
       processed. Please note that as post-up and  pre-down  are  aliases,  no
       files  in  the corresponding directories are processed.  Please use if-
       up.d and if-down.d directories instead.

       All  of  these  commands  have  access  to  the  following  environment
       variables.

       IFACE  physical name of the interface being processed

       LOGICAL
              logical name of the interface being processed

       ADDRFAM
              address family of the interface

       METHOD method of the interface (e.g., static)

       MODE   start if run from ifup, stop if run from ifdown

       PHASE  as per MODE, but with finer granularity, distinguishing the pre-
              up, post-up, pre-down and post-down phases.

       VERBOSITY
              indicates whether --verbose was used; set to 1 if so, 0 if not.

       PATH   the  command   search   path:   /usr/local/sbin:/usr/local/bin:-
              /usr/sbin:/usr/bin:/sbin:/bin

       Additionally,  all  options given in an interface definition stanza are
       exported to the environment in upper case with "IF_" prepended and with
       hyphens   converted  to  underscores  and  non-alphanumeric  characters
       discarded.

INET ADDRESS FAMILY

       This section documents  the  methods  available  in  the  inet  address
       family.

   The loopback Method
       This method may be used to define the IPv4 loopback interface.

       Options

              (No options)

   The static Method
       This  method  may be used to define ethernet interfaces with statically
       allocated IPv4 addresses.

       Options

              address address
                     Address (dotted quad/netmask) required

              netmask mask
                     Netmask (dotted quad or CIDR)

              broadcast broadcast_address
                     Broadcast address (dotted quad, + or -) Default value: +

              metric metric
                     Routing metric for default gateway (integer)

              gateway address
                     Default gateway (dotted quad)

              pointopoint address
                     Address of  other  end  point  (dotted  quad).  Note  the
                     spelling of "point-to".

              hwaddress address
                     Link local address.

              mtu size
                     MTU size

              scope  Address  validity  scope.  Possible values: global, link,
                     host

   The manual Method
       This method may be used to define interfaces for which no configuration
       is done by default. Such interfaces can be configured manually by means
       of up and down commands or /etc/network/if-*.d scripts.

       Options

              (No options)

   The dhcp Method
       This method may be used to obtain an address via DHCP with any  of  the
       tools:  dhclient, pump, udhcpc, dhcpcd. (They have been listed in their
       order of precedence.) If you have a complicated DHCP setup  you  should
       note  that  some of these clients use their own configuration files and
       do not obtain their configuration information via ifup.

       Options

              hostname hostname
                     Hostname to be requested (pump, dhcpcd, udhcpc)

              leasehours leasehours
                     Preferred lease time in hours (pump)

              leasetime leasetime
                     Preferred lease time in seconds (dhcpcd)

              vendor vendor
                     Vendor class identifier (dhcpcd)

              client client
                     Client identifier (dhcpcd, udhcpc)

              hwaddress address
                     Hardware Address.

   The bootp Method
       This method may be used to obtain an address via bootp.

       Options

              bootfile file
                     Tell the server to use file as the bootfile.

              server address
                     Use the  IP  address  address  to  communicate  with  the
                     server.

              hwaddr addr
                     Use  addr  as the hardware address instead of whatever it
                     really is.

   The tunnel Method
       This method is used to create GRE or IPIP tunnels. You need to have the
       ip  binary  from the iproute package. For GRE tunnels, you will need to
       load the ip_gre module and the ipip module for IPIP tunnels.

       Options

              address address
                     Local address (dotted quad) required

              mode type
                     Tunnel type (either GRE or IPIP) required

              endpoint address
                     Address of other tunnel endpoint required

              dstaddr address
                     Remote address (remote address inside tunnel)

              local address
                     Address of the local endpoint

              gateway address
                     Default gateway

              ttl time
                     TTL setting

              mtu size
                     MTU size

   The ppp Method
       This method uses pon/poff to  configure  a  PPP  interface.  See  those
       commands for details.

       Options

              provider name
                     Use name as the provider (from /etc/ppp/peers).

              unit number
                     Use number as the ppp unit number.

              options string
                     Pass string as additional options to pon.

   The wvdial Method
       This  method uses wvdial to configure a PPP interface. See that command
       for more details.

       Options

              provider name
                     Use name as the provider (from /etc/wvdial.conf).

   The ipv4ll Method
       This method uses avahi-autoipd to configure an interface with  an  IPv4
       Link-Layer  address  (169.254.0.0/16 family). This method is also known
       as APIPA or IPAC, and  often  colloquially  referred  to  as  "Zeroconf
       address".

       Options

              (No options)

IPX ADDRESS FAMILY

       This section documents the methods available in the ipx address family.

   The static Method
       This  method  may  be  used  to setup an IPX interface. It requires the
       ipx_interface command.

       Options

              frame type
                     type of ethernet frames to use (e.g. 802.2)

              netnum id
                     Network number

   The dynamic Method
       This method may be used to setup an IPX interface dynamically.

       Options

              frame type
                     type of ethernet frames to use (e.g. 802.2)

INET6 ADDRESS FAMILY

       This section documents the  methods  available  in  the  inet6  address
       family.

   The auto Method
       This  method  may  be  used  to  define  interfaces  with automatically
       assigned IPv6 addresses. Using this method on its own doesn't mean that
       RDNSS  options will be applied, too. To make this happen, rdnssd daemon
       must be installed, properly configured and running. If stateless DHCPv6
       support  is turned on, then additional network configuration parameters
       such as DNS and NTP servers will be retrieved from a DHCP server.

       Options

              privext int
                     Privacy extensions (RFC3041) (0=off, 1=assign, 2=prefer)

              dhcp int
                     Use stateless DHCPv6 (0=off, 1=on)

   The loopback Method
       This method may be used to define the IPv6 loopback interface.

       Options

              (No options)

   The static Method
       This method may be used to define interfaces with  statically  assigned
       IPv6 addresses. By default, stateless autoconfiguration is disabled for
       this interface.

       Options

              address address
                     Address (colon delimited) required

              netmask mask
                     Netmask (number of bits, eg 64) required

              gateway address
                     Default gateway (colon delimited)

              media type
                     Medium type, driver dependent

              hwaddress address
                     Hardware address

              mtu size
                     MTU size

              accept_ra int
                     Accept router advertisements (0=off, 1=on)

              autoconf int
                     Perform stateless autoconfiguration (0=off, 1=on)

              privext int
                     Privacy extensions (RFC3041) (0=off, 1=assign, 2=prefer)

              scope  Address validity scope. Possible  values:  global,  site,
                     link, host

   The manual Method
       This method may be used to define interfaces for which no configuration
       is done by default. Such interfaces can be configured manually by means
       of up and down commands or /etc/network/if-*.d scripts.

       Options

              (No options)

   The dhcp Method
       This  method  may be used to obtain network interface configuration via
       stateful DHCPv6 with dhclient. In stateful DHCPv6, the DHCP  server  is
       responsible for assigning addresses to clients.

       Options

              hwaddress address
                     Hardware address

   The v4tunnel Method
       This  method may be used to setup an IPv6-over-IPv4 tunnel. It requires
       the ip command from the iproute package.

       Options

              address address
                     Address (colon delimited)

              netmask mask
                     Netmask (number of bits, eg 64)

              endpoint address
                     Address of  other  tunnel  endpoint  (IPv4  dotted  quad)
                     required

              local address
                     Address of the local endpoint (IPv4 dotted quad)

              gateway address
                     Default gateway (colon delimited)

              ttl time
                     TTL setting

              mtu size
                     MTU size

   The 6to4 Method
       This  method  may  be  used to setup an 6to4 tunnel. It requires the ip
       command from the iproute package.

       Options

              local address
                     Address of the local endpoint (IPv4 dotted quad) required

              ttl time
                     TTL setting

              mtu size
                     MTU size

CAN ADDRESS FAMILY

       This section documents the methods available in the can address family.

   The static Method
       This method may be used to  setup  an  Controller  Area  Network  (CAN)
       interface. It requires the the ip command from the iproute package.

       Options

              bitrate bitrate
                     bitrate (1..1000000) required

              samplepoint samplepoint
                     sample point (0.000..0.999)

              loopback loopback
                     loop back CAN Messages (on|off)

              listenonly listenonly
                     listen only mode (on|off)

              triple triple
                     activate triple sampling (on|off)

              oneshot oneshot
                     one shot mode (on|off)

              berr berr
                     activate berr reporting (on|off)

KNOWN BUGS/LIMITATIONS

       The  ifup  and ifdown programs work with so-called "physical" interface
       names.   These  names  are  assigned  to  hardware   by   the   kernel.
       Unfortunately  it can happen that the kernel assigns different physical
       interface names to the same hardware at different times;  for  example,
       what  was  called  "eth0" last time you booted is now called "eth1" and
       vice versa.  This creates a  problem  if  you  want  to  configure  the
       interfaces  appropriately.   A  way to deal with this problem is to use
       mapping scripts that choose logical interface names  according  to  the
       properties  of  the  interface  hardware.   See  the get-mac-address.sh
       script in the examples directory for  an  example  of  such  a  mapping
       script.  See also Debian bug #101728.

AUTHOR

       The     ifupdown     suite     was    written    by    Anthony    Towns
       <aj@azure.humbug.org.au>.  This manpage was contributed  by  Joey  Hess
       <joey@kitenet.net>.

SEE ALSO

       ifup(8), ip(8), ifconfig(8), run-parts(8).

       For  advice  on configuring this package read the Network Configuration
       chapter   of   the    Debian    Reference    manual,    available    at
       http://www.debian.org/doc/manuals/debian-reference/ch05.en.html  or  in
       the debian-reference-en package.

       Examples  of   how   to   set   up   interfaces   can   be   found   in
       /usr/share/doc/ifupdown/examples/network-interfaces.gz.