man > interfaces(5)

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 information for the ifup(8)
       and ifdown(8) commands.  This is where you configure how your system is connected to the net‐
       work.

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,  com‐
       ments 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-", "rename", "source"
       and "source-directory" stanzas. These will be described in more detail in the following  sec‐
       tions.

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 auto‐
       matically by various subsystems. This may be done using a command such as "ifup  --allow=hot‐
       plug  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  al‐
       ready  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 interfaces 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 powerful 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 re‐
       named 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 spec‐
       ifying them individually or using shell globs. Additionally, 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 located at /etc/network/interfaces, paths to the included files are un‐
       derstood 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 directory.

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  map‐
       ping  stanza must contain a script definition.  The named script is run with the physical in‐
       terface 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  exam‐
       ples 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 inter‐
       face as that logical 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
       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  net‐
       working,  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  avail‐
       able  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.)  A list of packages  providing  additional
       options is mentioned in the section "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  con‐
       figured addresses and options for that interface will be applied when bringing up that inter‐
       face.   This  is  useful to configure both IPv4 and IPv6 addresses on the same interface (al‐
       though 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 interface.

PATTERN MATCHING INTERFACES
       It is possible to use patterns to match one or more real interfaces.  These patterns can cur‐
       rently appear in lines beginning with "auto", "allow-", "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 operating system kernel and whose names match the pattern.  For example, given  the  fol‐
       lowing 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 interface 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 parent 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 inter‐
       face.  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 hotplugged), the interface eth0 and the VLAN in‐
       terface 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 auto‐
       matically brought down whenever their parent interfaces are brought down.

IFACE OPTIONS
       The following "command" options are available for every family and method.  Each of these op‐
       tions 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 ex‐
              its 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 decon‐
              figured), 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 always 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) after 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 correspond‐
       ing 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 variables:

       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 below).

       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.

       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  envi‐
       ronment  in  upper  case  with  "IF_" prepended and with hyphens converted to underscores and
       non-alphanumeric characters discarded.

       When ifupdown is being called with the --all option, before doing anything 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  parameter  (or  "auto"  if  it's  not  set),  ADDRFAM="meta"  and
       METHOD="none".   After all the interfaces have been brought up or taken down, the appropriate
       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 commands 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 interface than the one that is already being
       (de)configured.  Loops are detected and will result in the call failing instead  of  a  dead‐
       lock, although 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.  How‐
       ever, other packages can make other options available  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-freshclam, controlaula,
       epoptes-client, ethtool, guidedog, hostap-utils, hostapd, htpdate, ifenslave, ifmetric, ifup‐
       down-extra, ifupdown-multi, ifupdown-scripts-zg2, initscripts, isatapd, linux-wlan-ng, lprng,
       macchanger, miredo, nslcd, ntpdate,  openntpd,  openresolv,  openssh-server,  openvpn,  open‐
       vswitch-switch,  postfix,  resolvconf,  sendmail-base,  shorewall-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  ad‐
       dresses.

       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. 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 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/net‐
       work/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, ud‐
       hcpc, 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 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.  Us‐
       ing 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. 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+forwarding). 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. Default 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 de‐
       fault, 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+forwarding)

              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). Default 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/net‐
       work/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+forwarding). 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. Default 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) required

              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) required

              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 command 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) 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)

              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.  Unfortunately it can happen that the kernel assigns dif‐
       ferent 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 prob‐
       lem 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 AT azure.au>.  This manpage was
       contributed by Joey Hess <joey AT 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.debian.org/doc/manuals/debian-refer
       ence/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/net‐
       work-interfaces.gz.

ifupdown                                    24 July 2017                               INTERFACES(5)
interfaces(5)
NAME DESCRIPTION EXAMPLE FILE FORMAT INTERFACE SELECTION INTERFACE RENAMING INCLUDING OTHER FILES MAPPINGS INTERFACE DEFINITIONS INTERFACE TEMPLATES PATTERN MATCHING INTERFACES VLAN INTERFACES IFACE OPTIONS HOOK SCRIPTS ENVIRONMENT VARIABLES CONCURRENCY AND PARALLEL EXECUTION OPTIONS PROVIDED BY OTHER PACKAGES INET ADDRESS FAMILY
The loopback Method Options The static Method Options The manual Method Options The dhcp Method Options The bootp Method Options The tunnel Method Options The ppp Method Options The wvdial Method Options The ipv4ll Method Options
IPX ADDRESS FAMILY
The static Method Options The dynamic Method Options
INET6 ADDRESS FAMILY
The auto Method Options The loopback Method Options The static Method Options The manual Method Options The dhcp Method Options The tunnel Method Options The v4tunnel Method Options The 6to4 Method Options
CAN ADDRESS FAMILY
The static Method Options
KNOWN BUGS/LIMITATIONS AUTHOR SEE ALSO

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