From Linux Man Pages
ifcfg - common elements of network interface configuration
/etc/sysconfig/network/ifcfg-*
VARIABLES
The following is a list of variables that can be put in the configuration file, with an example in parentheses.
* marks the default. For the meaning of suffix, see the section Multiple addresses.
STARTMODE {manual*|auto|hotplug|ifplugd|nfsroot|off}
Choose when the interface should be set up.
manual Interface will be set up if ifup is called manually (without option boot or hotplug)
auto Interface will be set up as soon as it is available (and service network was started). This either
happens at boot time when network is starting or via hotplug when a interface is added to the sys-
tem (by adding a device or loading a driver). To be backward compliant onboot, on and boot are
aliases for auto.
hotplug
This mode is nearly the same as auto. The difference between auto and hotplug is that the latter
does not make rcnetwork fail if the interface cannot be brought up.
ifplugd
The interface will be controlled from ifplugd. At initial ifup only iflugd will be started for this
interface. Then if ifplugd detects a link if calls ifup again which finally sets the interface up.
See also variable IFPLUGD_PRIORITY below.
nfsroot
Nearly like auto, but interfaces with this startmode will never be shut down via rcnetwork stop.
ifdown <interface> still works. Use this when you use a root filesystem via network.
off Will never be activated.
IFPLUGD_PRIORITY
If there multiple interfaces have STARTMODE=ifplugd and a nonzero priority, only one of them will be set
up at a time. Everytime one of these interfaces is (un)plugged the interface with highest priority (and
plugged cable) will be set up.
BOOTPROTO {static*|dhcp|autoip|dhcp+autoip|6to4}
Setup protocol. If this variable is empty, missing or static, a fixed address is used. Fixed addresses may
also be configured together with dhcp. autoip may be used for a zeroconf setup. dhcp+autoip falls back
to autoip if dhcp fails.
Use 6to4 to set up IPv6 tunnel interfaces running in the "6to4" mode. See also ifcfg-tunnel(5).
IPADDR[suffix] {IPv4|IPv6}[/PREFIXLEN]
IP address, either IPv4 or IPv6. You may add /<prefixlenght> in both cases and omit NETMASK or PREFIXLEN.
If you need more then one IP address use this variable multiple times with different suffixes added. See
section Multiple addresses below. If no address is configured the interface will just be activated (UP).
PREFIXLEN[suffix]
Number of bits in IPADDR that form the network address. Alternatively add prefixlength to IPADDR or use
NETMASK. PREFIXLEN is preferred over NETMASK. but highest priority has a prefixlength added to the IP
address in the variable IPADDR.
NETMASK[suffix]
Network mask. Alternatively add prefixlength to IPADDR or use PREFIXLEN. This variable is ignored if a
prefixlength is specified.
BROADCAST[suffix]
Network broadcast. If you omit the broadcast address, it will be calculated from netmask or prefixlength.
You can affect the calculation with the variable DEFAULT_BROADCAST in /etc/sysconfig/network/config. See
the description there.
REMOTE_IPADDR[suffix]
The remote IP address of a point to point connection
LABEL[suffix]
Each address may be tagged with a label string. In order to preserve compatibility with Linux-2.0
net aliases, this string must coincide with the name of the device or must be prefixed with the device
name followed by colon. This may be useful with Multiple addresses (see below).
SCOPE[suffix]
The scope of the area where this address is valid. The available scopes are listed in file
/etc/iproute2/rt_scopes. Predefined scope values are:
global - the address is globally valid.
site - (IPv6 only) the address is site local, i.e. it is valid inside this site.
link - the address is link local, i.e. it is valid only on this device.
host - the address is valid only inside this host.
MTU Set the maximum transfer unit (MTU) for this interface.
IP_OPTIONS[suffix]
Any other option you may want to give to the ip add addr ... command. This string is appended to the com-
mand.
LLADDR Set an individual link layer address (MAC address).
LINK_OPTIOS
Here you may add any option valid with ip link set up ...
INTERFACETYPE
Sometimes ifup cannot determine the interface type properly. In this cases you may specify it in this
variable.
ETHTOOL_OPTIONS
If this variable is not empty ifup will call ethtool with this options. See manpage ethtool(8) for avail-
able options. If option string starts with a '-' (e.g. '-K iface rx on') then the second word in the
string will be replaced with the current interface name. Else (e.g. 'autoneg off speed 10') ifup prepends
'-s <interface>'.
RUN_POLL_TCPIP {yes*|no}
Controls running /etc/ppp/poll.tcpip when a dialup connection is established.
NM_CONTROLLED {yes|no*}
If the network is managed with NetworkManager but you want to control an interface manually with ifup/down
you can set this variable to 'yes'.
PRE_UP_SCRIPT, POST_UP_SCRIPT, PRE_DOWN_SCRIPT and POST_DOWN_SCRIPT
Here you can hook a script (better: an executable) to perform individual actions before/after the inter-
face is set up or before/after the interface is set down. If you use relative filenames ifup will look
for them in /etc/sysconfig/network/scripts but you may use absolute paths as well. They were called
scripts, because they usually are scripts, but you may add also binaries here. If they are scripts, they
must be made executable.
These scripts will be called with nearly the same arguments as ifup. The only difference is that the con-
figuration-name (optional for ifup) is always set with the name determined by getcgf. The configuration
name is stored in the variable $CONFIG which may be used inside the ifcfg- configuration file.
If BOOTPROTO=dhcp then the post up and pre down scripts will not be executed immediately by ifup/ifdown.
Instead dhcpcd calls ifup/ifdown with a special option always after it sets, changes or removes the IP
address. Therefore post up scripts will be excuted after the interface is really up which may be much
later if dhcp did not get a lease immedialetly. And pre down scripts are called after dhcp shut down the
interface (not before as 'pre' would indicate. This is a problem of dhcpcd).
TUNNEL, TUNNEL_LOCAL_IPADDR, TUNNEL_LOCAL_INTERFACE, TUNNEL_REMOTE_IPADDR, T
Using this variable you may set up different tunnels. See manpage ifcfg-tunnel(5).
ETHERDEVICE
Needed only for virtual LANs. It contains the real interface to use for the vla interface. See manpage
ifcfg-vlan(5).
BONDING_MASTER, BONDING_SLAVE_*, BONDING_OPTS, BONDING_MODULE_OPTS
These are used to set up interface bonding. See manpage ifcfg-bonding(5).
GENERAL VARIABLES
There are some general settings in the file /etc/sysconfig/network/config. If needed you can also set every gen-
eral variable as an individual variable in the ifcfg-* files.
DEFAULT_BROADCAST
GLOBAL_POST_UP_EXEC
GLOBAL_PRE_DOWN_EXEC
CHECK_DUPLICATE_IP
DEBUG
USE_SYSLOG=
MODIFY_RESOLV_CONF_DYNAMICALLY
MODIFY_NAMED_CONF_DYNAMICALLY
MODIFY_RESOLV_CONF_STATIC_DNS
CONNECTION_SHOW_WHEN_IFSTATUS
CONNECTION_CHECK_BEFORE_IFDOWN
CONNECTION_CLOSE_BEFORE_IFDOWN
CONNECTION_UMOUNT_NFS_BEFORE_IFDOWN
CONNECTION_SEND_KILL_SIGNAL
MANDATORY_DEVICES
WAIT_FOR_INTERFACES
FIREWALL
LINKLOCAL_INTERFACES
IFPLUGD_OPTIONS
Please see the description of these variables in /etc/sysconfig/network/config.
Multiple addresses
You can extend the variable name IPADDR by any string you like. For example IPADDR_1, IPADDR-FOO or IPADDRxxx.
Use these variables for your IP addresses. If you need some additional parameters for these addresses, then just
add the same extension to these variable names: BROADCAST, NETMASK, PREFIXLEN, REMOTE_IPADDR, LABEL, SCOPE,
IP_OPTIONS.
Example:
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 number as label for every addi-
tional address.
BUGS
Please report bugs at <http://www.suse.de/feedback>
RELATED
/etc/sysconfig/network/ifcfg.template, ifcfg-bonding(5), ifcfg-tunnel(5), ifcfg-vlan(5), ifcfg-wireless(5),
ifup(8).
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