IFUP(8)

NAME
ifup - start a preconfigured net interface.
ifdown - stop a (preconfigured) net interface.
ifstatus - show the state of a (preconfigured) net interface.

SYNOPSIS
if{up,down,status} [ <configuration-name> ] <hardware-description> [-o options ]

NOTATION
We use the terms configuration, interface and device in a dedicated way. A device is always a piece of hardware representing a network interface, a PCI or PCMCIA card or a 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 parameters 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 built-in 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. So even if the interface name changes the interface to a certain device will always have the right setup.

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.

ifdown is used to set down the interface and flush all its addresses. It is possible to let ifdown check the interface if it is still used before setting it down. If configured it may then get rid of the using processes or refuse setting it down. Have a look at /etc/sysconfig/network/config to enable this feature.

ifstatus checks if the interface and its routes were set up properly.

<hardware-description> may just be the interface name.
But it can be more. It describes the device of the interface to be set up. As there is no fixed relation between devices and the names their interfaces get from the kernel, it might be necessary to specify the device exactly. The hardware-description may be the current interface name, the MAC address or the bus location where the device resides. It has to be compliant with the device naming rules as specified in getcfg(8). ifup uses getcfg to obtain all missing information, for example the interface name of a device with given hardware-description.
ifup uses getcfg also to get the best matching configuration for the interface. Every configuration is stored in files below /etc/sysconfig/network which are named ifcfg-<configuration-name>.

<configuration-name> is the name of a configuration that should be used to set up the interface. It may be used to circumvent the automatic search for a configuration with getcfg. In this case the configuration names are not restricted. For example if you have a configuration file ifcfg-my-special you may call ifup my-special <hwdesc>.

OPTIONS

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

auto
    Only set up the interface if the configuration has the STARTMODE=auto (or boot, onboot or hotplug.)

[on]boot
    Alias for 'auto'.

hotplug
    Like auto, but do some extra jobs, because hotplug indicates that the interface was just (un)registered. These extra jobs contain (if configured): starting/stopping ifplugd, renaming interface and removing all status files at ifdown.

manual
    This is default operation mode and sets up interfaces with STARTMODE=manual. If option 'rc' is used which implies mode 'auto', you can force mode 'manual'.

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

dhcp
    Indicates that script is called from dhcp client. When a interface has BOOTPROTO=dhcp ifup/down does not execute any post action. After dhcp client got a lease and has set ip address, it calls ifup again, this time with option 'dhcp'. In this run we finish interface setup.

nodeps
    If there are interfaces based on this interface, ifdown takes these depending interfaces down first. If you don't like that, use 'nodeps'.

prov=<n>
    Use provider <n> instead that from config file. Only usefull for dialup interfaces.

quiet
    Suppress normal output.

debug
    Be verbose.

FILES
/sbin/ifup
    The script itself.
/etc/sysconfig/network/ifcfg-*
    The files containing the configuration of the devices. An example that shows a typical configuration with the name ifcfg-eth0:
    IPADDRESS=10.10.11.184
    NETMASK=255.255.0.0
    BROADCAST=10.10.255.255
    STARTMODE=onboot
/etc/sysconfig/network/ifroute-*
    You can specify individual routes for every configuration in these files. See routes (5) for a detailed description.
/etc/sysconfig/network/if-{up,down}.d/
    Scripts in these directories will be executed when any interface is started, if-up.d, and when any interface is stopped, if-down.d. They have to be executable and may also be binary. The execution of these programs is controlled 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.

GENERAL VARIABLES
There are some general settings in the file /etc/sysconfig/network/config. If needed you can also set every general variable as an individual variable in the ifcfg-* files. Please see the description of these variables in /etc/sysconfig/network/config.

rcnetwork
If the network script is called by a runlevel switch (e.g. at boot time) then it will only set up devices with STARTMODE=onboot. When the network script is called manually (or by any script) it will set up all STARTMODE=onboot and those configurations which were up before the last 'network stop'. That means if you already plugged in a pcmcia card, a rcnetwork restart will restart this interface as well as your changed configuration will be used. This feature is necessary for YaST or SuSE Configuration 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 (calling ip or ifconfig directly) it will just be shut down. Some background information on this: For every configuration that is set up with ifup manually or by a hotplug script, ifup stores the name of the used interface in runtime 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 information, 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/sysconfig/if-usb.

DIAGNOSTICS
ifstatus interface

BUGS
Please report bugs at <http://www.suse.de/feedback>

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
ifcfg(5), routes(5).