IFUP(8) Network configuration IFUP(8)NAMEifup - start a pre-configured network interface.
ifdown - stop a (pre-configured) network interface.
ifstatus - show the state of a (pre-configured) network interface.
ifrenew - renews the dhcp lease on a network interface.
ifprobe - checks if the configuration for the interface has changed
SYNOPSIS
if{up,down,status,renew,probe} [ <configuration-name> ] <interface> [-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.
DESCRIPTIONifup is used to bring up a pre-configured interface for networking. It
is usually invoked by the network script at boot time or by the PCM‐
CIA/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/net‐
work/config to enable this feature.
ifstatus checks if the interface and its routes were set up properly.
ifrenew is used to renew the dhcp lease on the desired interface with‐
out shutting the interface down. It only restarts the corresponding
dhcpcd or dhclient process.
ifprobe checks if any of the configuration files for this interface
have been changed since the interface is up. Checked files are the cor‐
responding ifcfg-*, ifroute-*, ifservices-* and common configuration
files config, dhcp and routes.
<interface> is the network interface name.
The network interface names of physical network devices are assigned by
the kernel and may be modified by udev(7) rules; see the PERSISTENT
INTERFACE NAMES section.
<configuration-name> is the optional parameter with the name of a con‐
figuration, that should be used to set up the interface. Every configu‐
ration is stored in files below /etc/sysconfig/network which are named
ifcfg-<configuration-name>. By default, the interface name is used as
configuration name. The parameter exists for compatibility reasons, but
may be also used to circumvent this fixed relation.
PERSISTENT INTERFACE NAMES
The support for persistent interface names for physical network devices
using ifcfg-<hardware-description> configuration files is removed from
sysconfig since openSUSE 10.3. Instead, an automatic assignment of per‐
sistent interface names is implemented using udev(7) rules.
When a network device driver is loaded, the kernel assigns the next
currently free interface name to it. 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 hot-pluggable devices. With such
devices (like PCMCIA or USB) you cannot always know which interface
name it will get - it depends for example on the order the devices got
plugged in.
The network interface assigned in the kernel is reported to the udev
daemon. When a device appears the first time, the udev persistent net
generator rule creates a rule matching the device, by default using the
hardware (MAC) address, that renames the interface name assigned by the
kernel to one, that is not used in any another rule and thus unique for
the device. This rule is appended to the persistent net rule file and
executed. When the same device appears in the system next time, the
generated rule renames the interface to the persistent name again.
The generated persistent interface name rules can be adopted in yast2
network module or by editing the rule file directly. Currently, they
are stored in the /etc/udev/rules.d/70-persistent-net.rules udev rule
file.
OPTIONS
The following are options to be specified after the -o switch.
auto Only set up the interface if the configuration has the START‐
MODE=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 inter‐
face has BOOTPROTO=dhcp ifup/down does not execute any post
action immediately. 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.
debug Be verbose.
(no)syslog
With nosyslog the scripts don't send messages to syslog even if
the configuration variable USE_SYSLOG is set to "yes". This is
default for ifstatus only. If you want also ifstatus messages
send to syslog then call it with syslog.
FILES
/sbin/ifup
The script itself.
/etc/sysconfig/network/config
General configuration options. See section GENERAL VARIABLES
below.
/etc/sysconfig/network/ifcfg- <configuration-name>
The files containing the configuration of the devices. An exam‐
ple 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- <configuration-name>
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 con‐
figuration file /etc/sysconfig/network/config These are not
interface specific, and can have any name. If you need inter‐
face/configfile specific scripts to be executed have a look at
PRE_UP_SCRIPT, POST_UP_SCRIPT, PRE_DOWN_SCRIPTand
POST_DOWN_SCRIPT.
/etc/sysconfig/network/ifservices- <configuration-name>/
If you don't have a permanent network connection and like that
certain services are not started at boot time unconditionally
but later after the network connection was established then you
can add these services here. See ifservices (5) for a detailed
description.
/etc/sysconfig/network/ifcfg.template
A template for writing ifcfg-* files.
GENERAL VARIABLES
There are some general settings in the file /etc/sysconfig/network/con‐
fig. If needed you can also set every general variable as an individ‐
ual variable in the ifcfg-* files. Please see the description of these
variables in /etc/sysconfig/network/config.
For dhcp there are additional global options in /etc/sysconfig/net‐
work/dhcp. Also these are described there and can be used individually
in ifcfg-* files.
rcnetwork (/etc/init.d/network)
At boot time network devices are initialized asynchronously via hot‐
plug. Once this initialization process registered an interface for it
this will also trigger a hotplug event which will call ifup. If service
network was still not started ifup will just exit. As soon as service
network is active ifup will do its job and set up the interface. There‐
fore the job of the network start script consists of:
- set the 'network active' flag
- set up all interfaces already available
- wait for mandatory interfaces which are still not there
- set up tunnel, vlan, et al.
At boot time the scripts tries to determine the list of mandatory
devices automatically. It considers all interfaces that have a start‐
mode 'auto' or 'onboot' as mandatory. Normally it waits 20 seconds for
them and exits then with failed is any mandatory interface is still
missing.
Alternatively you may specify all mandatory devices manually in the
variable MANDATORY_DEVICES in the file. /etc/sysconfig/network/config.
There you may also tweak the timeout in WAIT_FOR_INTERFACES.
The network script will only set up devices with with startmodes auto,
onboot or hotplug. To set up an interface with startmode manual you
have to call ifup manually. (rcnetwork calls 'ifup ... -o rc').
DIAGNOSTICS
ifstatus interface
ifup and rcnetwork write status files in /dev/.sysconfig/network. If
something went completely wrong this files might be interesting.
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 manual page
Michal Ludvig <mludvig@suse.cz> -- tunnel support
SEE ALSOifcfg(5), routes(5), ifservices(5), ifcfg-wireless(5), ifcfg-tunnel(5),
ifcfg-vlan(5), ifcfg-bonding(5), getcfg(8).
sysconfig August 2004 IFUP(8)
