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INTERFACES(5)                     File formats                    INTERFACES(5)

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

DESCRIPTION
       /etc/network/interfaces contains network interface configuration  infor-
       mation  for  the ifup(8) and ifdown(8) commands.  This is where you con-
       figure how your system is connected to the network.

EXAMPLE
       The following example configures two network interfaces: eth0 is brought
       up at boot, and uses DHCP for IPv4 and SLAAC for IPv6, whereas  eth1  is
       brought  up whenever the network hardware is detected, and is configured
       with static IPv4 and IPv6 addresses.

       auto eth0
       allow-hotplug eth1

       iface eth0 inet dhcp

       iface eth0 inet6 auto

       iface eth1 inet static
            address 192.168.1.2/24
            gateway 192.168.1.1

       iface eth1 inet6 static
            address fec0:0:0:1::2/64
            gateway fec0:0:0:1::1

FILE FORMAT
       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 charac-
       ter a backslash.

       The file consists of zero or more "iface", "mapping", "auto",  "allow-",
       "rename",  "source"  and  "source-directory"  stanzas. These will be de-
       scribed in more detail in the following sections.

INTERFACE SELECTION
       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 also used by the system boot  scripts,  so  interfaces  marked
       "auto"  are  brought  up at boot time.)  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 subsystems.  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.  (Interfaces
       marked "allow-hotplug" are brought up when udev detects them.  This  can
       either be during boot if the interface is already present, or at a later
       time, for example when plugging in a USB network card.  Please note that
       this  does  not have anything to do with detecting a network cable being
       plugged in.)

       Lines beginning with "no-auto-down" are used to identify interfaces that
       should not be brought down by the command "ifdown -a". Its main  use  is
       to  prevent  an interface from being brought down during system shutdown
       time, for example if the root filesystem is a network filesystem and the
       interface should stay up until the very end. Note  that  you  can  still
       bring down the interface by specifying the interface name explicitly.

       Lines  beginning  with  "no-scripts" are used to identify interfaces for
       which scripts in /etc/network/if-*.d/ should not be run when  those  in-
       terfaces are brought up or down.  he above will match eth0 and eth1, and
       will bring up both interfaces using the "iface eth" stanza.

INTERFACE RENAMING
       Lines  beginning  with "rename" are used to rename interfaces.  It takes
       one or more arguments in the form of "CUR=NEW", where CUR is the name of
       an existing interface, and NEW is the new name.  This becomes very  pow-
       erful when combined with pattern matching for the CUR interface.

       Interfaces  are  renamed  whenever "ifup" is called.  Renaming logically
       happens before anything else is done.  So if  an  interface  is  started
       with the name "foo", and it has to be renamed to "bar" and brought up at
       boot  time,  then  one  should use the following /etc/network/interfaces
       file:

       rename foo=bar
       auto bar
       iface bar ...

       However, if the interface is not renamed yet, it is possible to use both
       "ifup foo" and "ifup bar".  The former command will  then  automatically
       be  converted  to the latter.  This is mainly useful when ifup is called
       automatically whenever an interface is hotplugged.

       Interface renaming only works if the operating system supports it, if an
       interface is not renamed to another existing interface, and may  require
       that  the  interface  that is to be renamed has not been brought up yet.
       If ifup tries to rename an interface and it fails, it will exit with  an
       error.

INCLUDING OTHER FILES
       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.)

       Similarly, "source-directory" keyword is used to source  multiple  files
       at  once, without specifying them individually or using shell globs. Ad-
       ditionally, when "source-directory" is used,  names  of  the  files  are
       checked  to match the following regular expression: ^[a-zA-Z0-9_-]+$. In
       other words, the names must consist entirely of ASCII upper- and  lower-
       case  letters, ASCII digits, ASCII underscores, and ASCII minus-hyphens.
       In the directory path, shell wildcards may be used as well.

       When sourcing files or directories, if a path  doesn't  have  a  leading
       slash,  it's considered relative to the directory containing the file in
       which the keyword is placed. In the example above, if the  file  is  lo-
       cated at /etc/network/interfaces, paths to the included files are under-
       stood to be under /etc/network.

       By  default,  on  a freshly installed Debian system, the interfaces file
       includes a line to source files in the /etc/network/interfaces.d  direc-
       tory.

MAPPINGS
       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 stan-
       dard output before exiting. See /usr/share/doc/ifupdown/examples for ex-
       amples 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 in-
       terface.  It then maps this name, possibly more than once  according  to
       successive mapping specifications,  until no further mappings are possi-
       ble.   If  the resulting name is the name of some defined logical inter-
       face then ifup attempts to bring up the physical interface as that logi-
       cal interface.  Otherwise ifup exits with an error.

INTERFACE DEFINITIONS
       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 de-
       fault 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").  Fol-
       lowing 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 de-
       scribed 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 config-
       ure  the interface using iwconfig(8).  (See wireless(7) for details.)  A
       list of packages providing additional options is mentioned in  the  sec-
       tion "OPTIONS PROVIDED BY OTHER PACKAGE".

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

       Multiple "iface" stanzas can be given for the same interface,  in  which
       case all of the configured addresses and options for that interface will
       be applied when bringing up that interface.  This is useful to configure
       both IPv4 and IPv6 addresses on the same interface (although if no inet6
       stanza  is present, the kernel will normally still perform stateless ad-
       dress autoconfiguration if there is an IPv6 route  advertisement  daemon
       on  the network). It can also be used to configure multiple addresses of
       the same type on a single interface.

INTERFACE TEMPLATES
       It is possible to define interface definition templates and extend  them
       using the inherits keyword:

       iface ethernet inet static
            mtu 1500
            hwaddress 11:22:33:44:55:66

       iface eth0 inet static inherits ethernet
            address 192.168.1.2/24

       This  may  be  useful to separate link-level settings shared by multiple
       interfaces from, for example, IP address settings specific to every  in-
       terface.

PATTERN MATCHING INTERFACES
       It  is  possible  to  use patterns to match one or more real interfaces.
       These patterns can currently appear in lines beginning with "auto", "al-
       low-", "rename" and on the command line.  A pattern  has  the  following
       format (see below for exceptions for GNU/Hurd):

       [VARIABLE]/VALUE[/[OPTIONS]][=LOGICAL]

       If no VARIABLE is given, this pattern will match interface names against
       the  given  VALUE.  VALUE can contain wildcard patterns such as ? and *,
       see the fnmatch(3) function.  When ifup or ifdown is run,  patterns  are
       replaces  by all real interfaces that are currently known to the operat-
       ing system kernel and whose names match the pattern.  For example, given
       the following line:

       auto /eth*

       If the kernel knows about the interfaces with names lo, eth0  and  eth1,
       then the above line is then interpreted as:

       auto eth0 eth1

       Note  that  there  must still be valid "iface" stanzas for each matching
       interface.  However, it is possible to combine a pattern with a  mapping
       to a logical interface, like so:

       auto /eth*=eth
       iface eth inet dhcp

       Valid  variable  names are "mac", in which case value is matched against
       the interface's MAC address.  On Linux, the variable name  can  also  be
       any  filename  in  /sys/class/net/<iface>/,  in  which case the value is
       matched against the contents of the corresponding file.

       The OPTIONS field currently only supports a number. If given,  only  the
       n-th  interface that has a matching value will actually be used, where n
       is the number given, starting at 1. So /eth*/1 will match the first  in-
       terface whose name starts with eth.

       On  GNU/Hurd,  interface  names  start  with  /dev/,  and this obviously
       clashes with the format for patterns.  To ensure an interface name  like
       /dev/eth0 does not get interpreted as a pattern, any pattern that starts
       with  /dev/  is  ignored, and instead interpreted as a literal interface
       name.  To make a pattern that matches interface names on  GNU/Hurd,  use
       something like:

       auto /?dev?eth*=eth
       iface eth inet dhcp

VLAN INTERFACES
       To ease the configuration of VLAN interfaces, interfaces having .  (full
       stop  character) in the name are configured as 802.1q tagged virtual LAN
       interface. For example, interface eth0.1 is  a  virtual  interface  with
       VLAN ID 1 having eth0 as its parent interface.

       VLAN  interfaces are mostly treated as independent interfaces.  As such,
       a VLAN interface is normally not automatically brought up when its  par-
       ent  interface is brought up.  The exception is when ifup is called with
       the --allow option, in which case all VLAN interfaces that  are  in  the
       same  allow  class  as the parent interface are brought up together with
       the parent interface.  For example:

       allow-hotplug eth0 eth0.1

       iface eth0 inet static
            address ...

       iface eth0.1 inet static
            address ...

       iface eth0.2 inet static
            address ...

       In the above example, when "ifup --allow hotplug eth0" is called (either
       manually or because udev triggers this when a  network  device  is  hot-
       plugged),  the  interface eth0 and the VLAN interface eth0.1 are brought
       up, but eth0.2 is not.

       Keep in mind that pattern matching will only match interfaces the kernel
       knows about, so it is not possible to specify "auto  /eth0.*"  and  have
       all VLAN interfaces for eth0 be brought up at boot time.  Another way to
       ensure that a VLAN interface is brought up automatically when the parent
       interface is brought up, is to use a recursive call to ifup, like so:

       iface eth0 inet manual
            up ifup eth0.3

       iface eth0.3 inet static
            address ...

       Note that there is no need to add an explicit call to ifdown, since VLAN
       interfaces  are  automatically brought down whenever their parent inter-
       faces are brought down.

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 them with "|| 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.

       description name
              Alias interface by name

HOOK SCRIPTS
       There are four directories in which scripts can be placed which will al-
       ways  be  run for any interface during certain phases of ifup and ifdown
       commands. These are:

       /etc/network/if-pre-up.d/
              Scripts in this directory are run before bringing  the  interface
              up.

       /etc/network/if-up.d/
              Scripts  in  this  directory are run after bringing the interface
              up.

       /etc/network/if-down.d/
              Scripts in this directory are run before bringing  the  interface
              down.

       /etc/network/if-post-down.d/
              Scripts  in  this  directory are run after bringing the interface
              down.

       The scripts in which are run (with no arguments) using run-parts(8)  af-
       ter  the  corresponding  pre-up,  up,  down and post-down options in the
       /etc/network/interfaces file itself have  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.

ENVIRONMENT VARIABLES
       All hook scripts, and the commands executed by pre-up, up, post-up, pre-
       down, down and post-down have access to the following environment  vari-
       ables:

       IFACE  The  physical  name  of the interface being processed, or "--all"
              (see below).

       LOGICAL
              The logical name of the interface being processed, or "auto" (see
              below).

       ADDRFAM
              The address family of the interface, or "meta" (see below).

       METHOD The method of the interface (e.g., static), or  "none"  (see  be-
              low).

       CLASS  The  class  of interfaces being processed.  This is a copy of the
              value given to the --allow option when running  ifup  or  ifdown,
              otherwise it is set to "auto" when the --all option is used.

       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 dis-
       carded.

       When ifupdown is being called with the --all option, before  doing  any-
       thing to interfaces, it calls all the hook scripts (pre-up or down) with
       IFACE  set to "--all", LOGICAL set to the current value of --allow para-
       meter (or "auto" if it's not  set),  ADDRFAM="meta"  and  METHOD="none".
       After  all the interfaces have been brought up or taken down, the appro-
       priate scripts (up or post-down) are executed.

CONCURRENCY AND PARALLEL EXECUTION
       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.  It is therefore
       important that any hook scripts and pre-up, up, down and post-down  com-
       mands are written with the possibility of parallel execution in mind.

       It  is allowed to recursively call ifup and ifdown from hook scripts and
       interface commands, as long as these calls refer to a  different  inter-
       face  than  the one that is already being (de)configured.  Loops are de-
       tected and will result in the call failing instead of  a  deadlock,  al-
       though it is best if one does not rely on that.

OPTIONS PROVIDED BY OTHER PACKAGES
       This  manual  page  documents  the configuration options provided by the
       ifupdown package.  However, other packages can make other options avail-
       able for use in /etc/network/interfaces.  Here is  a  list  of  packages
       that provide such extensions:

       arping,  avahi-autoipd, avahi-daemon, bind9, bridge-utils, clamav-fresh-
       clam,  controlaula,  epoptes-client,  ethtool,  guidedog,  hostap-utils,
       hostapd,  htpdate,  ifenslave, ifmetric, ifupdown-extra, ifupdown-multi,
       ifupdown-scripts-zg2, initscripts, isatapd, linux-wlan-ng,  lprng,  mac-
       changer,  miredo,  nslcd, ntpdate, openntpd, openresolv, openssh-server,
       openvpn, openvswitch-switch, postfix, resolvconf, sendmail-base,  shore-
       wall-init, slrn, slrnpull, tinc, ucarp, uml-utilities, uruk, vde2, vlan,
       vzctl, whereami, wide-dhcpv6-client, wireless-tools, wpasupplicant.

       Please consult the documentation of those packages for information about
       how they extend ifupdown.

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 number of bits) deprecated

              broadcast broadcast_address
                     Broadcast address (dotted quad, + or  -)  deprecated.  De-
                     fault 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 or "random".

              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

              hwaddress address
                     Link local address or "random".

              mtu size
                     MTU size

   The dhcp Method
       This  method  may  be used to obtain an address via DHCP with any of the
       tools: dhclient, 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 (dhcpcd, udhcpc)

              metric metric
                     Metric for added routes (dhclient)

              leasetime leasetime
                     Preferred lease time in seconds (dhcpcd)

              vendor vendor_id
                     Vendor class identifier (dhcpcd)

              client client_id
                     Client identifier (dhcpcd), or "no" (dhclient)

              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

              metric metric
                     Routing metric for default gateway (integer)

              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  com-
       mands 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  fam-
       ily.

   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 op-
       tions  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.  Please  note
       that on ifdown, the lease is not currently released (a known bug).

       Options

              privext int
                     Privacy extensions (RFC4941) (0=off, 1=assign, 2=prefer)

              accept_ra int
                     Accept  router  advertisements (0=off, 1=on, 2=on+forward-
                     ing). Default value: "2"

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

              request_prefix int
                     Request a prefix through DHCPv6 Prefix Delegation  (0=off,
                     1=on). Default value: "0"

              ll-attempts
                     Number  of  attempts to wait for a link-local address. De-
                     fault value: "60"

              ll-interval
                     Link-local address polling interval  in  seconds.  Default
                     value: "0.1"

   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/netmask) required

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

              metric metric
                     Routing metric for default gateway (integer)

              gateway address
                     Default gateway (colon delimited)

              media type
                     Medium type, driver dependent

              hwaddress address
                     Hardware address or "random"

              mtu size
                     MTU size

              accept_ra int
                     Accept  router  advertisements (0=off, 1=on, 2=on+forward-
                     ing)

              autoconf int
                     Perform stateless autoconfiguration (0=off, 1=on). Default
                     value: "0"

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

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

              preferred-lifetime int
                     Time that address remains preferred

              dad-attempts
                     Number  of  attempts to settle DAD (0 to disable DAD). De-
                     fault value: "60"

              dad-interval
                     DAD state polling  interval  in  seconds.  Default  value:
                     "0.1"

   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

              hwaddress address
                     Hardware address or "random"

              mtu size
                     MTU size

   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 or "random"

              accept_ra int
                     Accept  router  advertisements (0=off, 1=on, 2=on+forward-
                     ing). Default value: "1"

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

              request_prefix int
                     Request a prefix through DHCPv6 Prefix Delegation  (0=off,
                     1=on). Default value: "0"

              ll-attempts
                     Number  of  attempts to wait for a link-local address. De-
                     fault value: "60"

              ll-interval
                     Link-local address polling interval  in  seconds.  Default
                     value: "0.1"

   The tunnel Method
       This  method is used to create IP6GRE, IP6IP6 or IPIP6 tunnels. You need
       to have the ip binary from the iproute package. For IP6GRE tunnels,  you
       will  need  to  load  the  ip6_gre  module and the ip6_tunnel module for
       IP6IP6 or IPIP6 tunnels.

       Options

              address address
                     Local Address (colon delimited)

              netmask mask
                     Netmask (number of bits, eg 64)

              mode type
                     Tunnel type (either IP6GRE, IP6IP6 or IPIP6) required

              endpoint address
                     Address of other tunnel  endpoint  (colon  delimited)  re-
                     quired

              dstaddr address
                     Remote address (remote address inside tunnel)

              local address
                     Address of the local endpoint (colon delimited)

              metric metric
                     Routing metric for default gateway (integer)

              gateway address
                     Default gateway (colon delimited)

              ttl time
                     TTL setting

              mtu size
                     MTU size

              encaplimit limit
                     Encapsulation limit ("none" or integer)

   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) required

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

              endpoint address
                     Address of other tunnel endpoint (IPv4  dotted  quad)  re-
                     quired

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

              metric metric
                     Routing metric for default gateway (integer)

              gateway address
                     Default gateway (colon delimited)

              ttl time
                     TTL setting

              mtu size
                     MTU size

              preferred-lifetime int
                     Time that address remains preferred

   The 6to4 Method
       This  method may be used to setup a 6to4 tunnel. It requires the ip com-
       mand from the iproute package.

       Options

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

              metric metric
                     Routing metric for default gateway (integer)

              ttl time
                     TTL setting

              mtu size
                     MTU size

              preferred-lifetime int
                     Time that address remains preferred

CAN ADDRESS FAMILY
       This section documents the methods available in the can address family.

   The static Method
       This method may be used to setup a Controller Area Network (CAN)  inter-
       face. 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)

              restart-ms restart-ms
                     restart-ms (0..)

KNOWN BUGS/LIMITATIONS
       The  ifup  and  ifdown programs work with so-called "physical" interface
       names.  These names are assigned to hardware by  the  kernel.   Unfortu-
       nately  it  can happen that the kernel assigns different physical inter-
       face 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 ex-
       amples  directory for an example of such a mapping script.  See also De-
       bian bug #101728.

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

SEE ALSO
       ifup(8), ip(8), ifconfig(8), run-parts(8), resolvconf(8).

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

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

ifupdown                          24 July 2017                    INTERFACES(5)

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