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ifup


       ifstatus  - show the state of a (preconfigured) net inter­
       face.


SYNOPSIS

       if{up,down,status} config [ interface ] [-o options ]


NOTATION

       We use the terms configuration, interface and device in  a
       dedicated  way.  A  device is always the piece of hardware
       representing a network interface, the PCI- or  PCMCIA-card
       or  an  USB  device.  An interface then is the name of the
       network interface it gets from the kernel when the  device
       has  been  registered. A configuration is a set of parame­
       ters which  can  be  assigned  to  an  interface  like  ip
       addresses or routes.

       It  is  intentional  that a configuration does not need to
       belong to an interface,  but  to  a  device.  For  builtin
       devices there is most of the time a fixed relation between
       devices and interfaces, but this is  no  longer  the  case
       when  using  hotpluggable devices. With such devices (like
       PCMCIA or USB) you cannot always know which interface name
       you will get.


DESCRIPTION

       ifup  is  used  to  bring up a preconfigured interface for
       networking. It is usually invoked by the network script at
       boot  time or by the PCMCIA/hotplug system. It can also be
       used to start interfaces manually on the command line.  It
       activates  the  link,  adds addresses and other parameters
       and sets up the routes for an interface.

       config is the name of a configuration that should  be  set
       up.  In  most  cases  the  configuration is named like the
       interface to be used. In this case the argument  interface
       may  be  omitted.  But there are cases where the interface
       name is not known at configuration time.  For example with
       hotpluggable  devices  the  interface  name depends on the
       order the devices are plugged in. For this purpose  config
       may  be  a  description  of  the hardware that provides an
       interface. In this case the interface name  must  be  pro­
       vided as second argument.

       Every  configuration is stored in files below /etc/syscon­
       fig/network which  are  named  ifcfg-hw-description.   The
       name  of  the configuration is hw-description.  If you are
       just using fixed devices then hw-description is  just  the
       interface  name.  But if you have hotpluggable devices you
       may want to describe the hardware for a configuration more
       precisely.   hw-description  (or config) has the following
       syntax:
         {$interfacename,[$type-]$bustype[-$bus[-$id]],$mac}[:$alias]

       address. Then it uses the configuration that fits best  by
       dropping first $id, then $bus and last $type and/or adding
       $type.

       Examples: we have the following configuration files:
         ifcfg-eth0
         ifcfg-eth-usb
         ifcfg-pcmcia-1
       the table shows what configuration will be used with these
       ifup calls:
         ifup eth0                     ifcfg-eth0
         ifup usb-0-5 eth1             ifcfg-eth-usb
         ifup eth-pcmcia-1 eth1        ifcfg-pcmcia-1
         ifup eth-pcmcia-0 eth1        ---
         ifup eth-pcmcia-0 eth0        ifcfg-eth0

       The  name  of  the  finally  used  configuration is stored
       internally in the variable  $CONFIG.   You  may  use  this
       variable  when using hooked scripts. See section variables
       below.


OPTIONS

       The following are options to be  specified  after  the  -o
       switch.

       [on]boot
              Only set up the interface if the configuration  has
              the STARTMODE=onboot.

       hotplug
              Only  set up the interface if the configuration has
              the STARTMODE=hotplug.

       doalias
              Setup all aliases of a real interface.

       quiet  Suppress normal output.

       debug  Be verbose.

       rc     Special   option   for   the    use    in    rcnet­
              work (/etc/init.d/network).   See section rcnetwork
              below.


FILES

       /sbin/ifup
              The script itself.
       /etc/sysconfig/network/ifcfg-*
              The  files  containing  the  configuration  of  the
              devices.   An example that shows a typical configu­
              ration with the name ifcfg-eth0:
              by    the    variables    GLOBAL_POST_UP_EXEC   and
              GLOBAL_PRE_DOWN_EXEC in the  network  configuration
              file  /etc/sysconfig/network/config  These  are not
              interface specific, and can have any name.  If  you
              need  interface/configfile  specific  scripts to be
              executed   have   a    look    at    PRE_UP_SCRIPT,
              POST_UP_SCRIPT,         PRE_DOWN_SCRIPT         and
              POST_DOWN_SCRIPT.
       /etc/sysconfig/network/ifcfg.template
              A template for writing ifcfg- files.


VARIABLES

       The following is a list of variables that can  be  put  in
       the configuration file, with an example in parentheses.

       STARTMODE (onboot|manual|hotplug)
              Choose  when the configuration should be activated.
              At boot time, manually by the sysadmin  or  by  the
              PCMCIA/hotplug system.

       BOOTPROTO (static|dhcp|bootp|6to4)
              Setup  protocol.  If  missing  or "static", a fixed
              address is used. Note that bootp is  currently  not
              supported. (If you need it you will have to write a
              script ifup-bootp  and  place  it  in  /etc/syscon­
              fig/network/scripts.   And  we would of course like
              to know at <feedback@suse.de>)

              Use 6to4 to set up IPv6 tunnel  interfaces  running
              in  the  "6to4"  mode.  See also the section Tunnel
              interfaces below.

       IPADDR (10.20.1.29)

       IPADDR (3ffe:ffff:1::dead:beef/64)
              IP address, either IPv4 or IPv6. If you  need  more
              then  one IP address see section Multiple addresses
              below

       NETMASK (255.255.240.0)
              Network mask

       BROADCAST (10.20.15.255)
              Network  broadcast.  If  you  omit  the   broadcast
              address, it will be calculated from netmask or pre­
              fixlength. You can affect the calculation with  the
              variable  DEFAULT_BROADCAST  in /etc/sysconfig/net­
              work/config.  See the description there.

       REMOTE_IPADDR (192.168.42.242)
              The remote IP address of a point to point   connec­
              for  them in /etc/sysconfig/network/scripts but you
              may use absolute paths as well.

              You may use the internal variable  $CONFIG  in  the
              filename.  Note  that $CONFIG does contain the con­
              figuration that really is used by ifup and not what
              you  (or any system script) gave as the first argu­
              ment to ifup. See the  section  about  config  file
              matching above.

              These  scripts  will  be called with the same argu­
              ments as any other helper script.  This  is  almost
              the  arguments with which ifup was called, only the
              first argument  is  again  the  configuration  that
              really  is  used  by  ifup and not what you (or any
              system script) gave as the first argument to  ifup.
              See  again  the  section about config file matching
              above.


GENERAL VARIABLES

       There are some general settings in the  file  /etc/syscon­
       fig/network/config.  If needed you can also set every gen­
       eral variable as an individual  variable  in  the  ifcfg-*
       files.

       DEFAULT_BROADCAST

       CHECK_FOR_MASTER

       CHECK_DUPLICATE_IP

       DEBUG

       MODIFY_RESOLV_CONF_DYNAMICALLY

       MODIFY_NAMED_CONF_DYNAMICALLY

       CONNECTION_SHOW_WHEN_IFSTATUS

       CONNECTION_CHECK_BEFORE_IFDOWN

       CONNECTION_CLOSE_BEFORE_IFDOWN

       CONNECTION_UMOUNT_NFS_BEFORE_IFDOWN

       CONNECTION_SEND_KILL_SIGNAL

       Please see the description of these variables in
              /etc/sysconfig/network/config.


Multiple addresses (aka aliases)

              addresses,  then  just  add  the  same extension to
              these variable names.
                 IPADDR_AAA=1.2.3.4
                 NETMASK_AAA=255.0.0.0
                 BROADCAST_AAA=1.2.3.55
                 IPADDR_BBB=10.10.2.3/16
                 LABEL_BBB=BBB
                 and so on ...

       You do not need to set a label for any address.  But  then
       you should not use ifconfig any longer; go and use ip.  If
       you want to use ifconfig then omit the label for your main
       address  and  set  a  label  for every additional address.
       This is equivalent with using aliases with method 1.


Tunnel interfaces

       It is possible to create tunnel interfaces for three  dif­
       ferent  protocols:  SIT (IPv6 over IPv4 tunnel), GRE (uni­
       versal IPv4 tunnel) and  IPIP  (IPv4  over  IPv4  tunnel).
       Since  there  is not yet a YaST2 support for creating tun­
       nels one must write appropriate config files by  hand  for
       now.

       These new variables are to be used in tunnel config files:

       TUNNEL Here you have to set the tunnel protocol. This  may
              be  "sit" for IPv6 over IPv4 tunnel, "gre" for uni­
              versal IPv4 tunnel and "ipip" for  IPv4  over  IPv4
              tunnel.

       TUNNEL_LOCAL_IPADDR or TUNNEL_LOCAL_INTERFACE
              The  address  of  the  local  tunnel's end could be
              directly specified in TUNNEL_LOCAL_IPADDR variable.
              If  TUNNEL_LOCAL_IPADDR  is  empty  the  first ipv4
              address from the interface given  in  the  variable
              TUNNEL_LOCAL_INTERFACE will be used.

       TUNNEL_REMOTE_IPADDR

       TUNNEL_TTL
              Specify  the  Time To Life of the packet which car­
              ries the tunneled data. Usually it is set to 64 but
              in some circumstances you may want do use something
              else between 1 and 255. Special value is  "inherit"
              in  which  case  the  TTL  is copied from the inner
              (tunneled) packet. This is also the default if  the
              TTL variable wasn't used.

       TUNNEL_OPTIONS
              Here you may set additional options for the command
              ip tunnel add
                 STARTMODE='onboot'
                 BOOTPROTO='static'
                 TUNNEL='gre'
                 TUNNEL_LOCAL_IPADDR='192.168.1.2'
                 TUNNEL_REMOTE_IPADDR='172.16.2.3'
                 IPADDR='10.20.30.40'
                 TUNNEL_TTL='64'

              IPIP  tunnel  is  created  in exactly the same way,
              except that the variable TUNNEL has to  be  set  to
              "ipip"  in  this  case. Use filename ifcfg-ipip0 in
              this case.

       SIT tunnels for IPv6 over IPv4
              There are two modes in which SIT tunnels may  oper­
              ate: static and 6to4

              To  create  a  "static" tunnel one needs to know an
              IPv4 address of the remote end, while for a  "6to4"
              tunnel  the  remote  end  is  a "6to4 relay". These
              relays are usually  public  and  could  be  reached
              either under their respective IPv4 address or under
              a  unique  IPv4  anycast  address  192.88.99.1  (as
              defined in RFC 3068).

              This  typical  config file for a 6to4 tunnel should
              fit most user's needs and the only required  change
              is  the  external interface name. Default filename:
              ifcfg-sit1
                 STARTMODE='onboot'
                 BOOTPROTO='6to4'
                 TUNNEL='sit'
                 TUNNEL_LOCAL_INTERFACE='eth0'
                 TUNNEL_TTL='64'
              Additionally you need to set some routes.  Do  that
              in a file called ifroute-<configname> with the same
              configname as in ifcfg-<configname>. Default  file­
              name: ifroute-sit1 It may look like this:
                 2000::/3  2002:c058:6301::1  -  -  -  metric 1
              The  magic  string 2002:c058:6301::1 is a 6to4 ver­
              sion of the anycast IPv4 address 192.88.99.1.

              To create a "static" tunnel with local IPv6 address
              3ffe:ffff::1234/64  use  a  config  file like this:
              Default filename: ifcfg-sit1
                 STARTMODE='onboot'
                 BOOTPROTO='static'
                 TUNNEL='sit'
                 TUNNEL_LOCAL_IPADDR='192.168.1.2'
                 TUNNEL_REMOTE_IPADDR='172.16.2.3'
                 IPADDR='3ffe:ffff::1234/64'

       ration Profile Management (SCPM).

       Another  example:  If  you  have two network intefaces and
       configure one as onboot and the other as  manual  and  you
       never  brought  up  the  manual  interface, then rcnetwork
       restart will only stop and start the onboot interface. But
       if  you brought up the manual interface with ifup (that is
       important), then a restart will stop and  start  both.  If
       the  manual interface was brought up in another way (call­
       ing ip or ifconfig directly) it will just be shut down.

       Some background information on this: For every  configura­
       tion  that  is  set  up with ifup manually or by a hotplug
       script, ifup stores the name of the used interface in run­
       time  files  /var/run/sysconfig/if-config and deletes this
       info with ifdown.  rcnetwork calls ifup  with  the  option
       rc.   Therefore  ifup  does not store/delete this informa­
       tion, but looks if  it  finds  such  information  for  any
       interface with STARTMODE other than onboot.  ifup then may
       set up a configuration without giving the  interface  name
       as 2nd argument.  E.g. if you already plugged your USB NIC
       and did a rcnetwork stop  you  can  just  type  ifup  usb,
       because  the interface name was stored in /var/run/syscon­
       fig/if-usb.


DIAGNOSTICS

       ifstatus interface


BUGS

       Please report bugs at <feedback@suse.de>


AUTHOR

       Christian Zoz <zoz@suse.de> -- ifup script
       Michal Svec <msvec@suse.cz> -- ifup script
       Bjoern Jacke -- ifup script
       Mads Martin Joergensen <mmj@suse.de> -- ifup manpage
       Michal Ludvig <mludvig@suse.cz> -- tunnel support


SEE ALSO

       /etc/sysconfig/network/ifcfg.template, routes(5)

sysconfig                  January 2003                   IFUP(8)
  




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