linux 网卡配置文件详解

节选自：http://www.redhat.com/docs/manuals/enterprise/RHEL-3-Manual/ref-guide/s1-networkscripts-interfaces.html

Ethernet Interfaces

One of the most common interface files is
ifcfg-eth0, which controls the first Ethernet
network interface card[/i] or
NIC[/i] in the system. In a system with multiple
NICs, there are multiple
ifcfg-eth<X>
files (where <X> is a unique number
corresponding to a specific interface). Because each device has its own
configuration file, an administrator can control how each interface
functions individually.
The following is a sample ifcfg-eth0 file for a
system using a fixed IP address:

DEVICE=eth0 BOOTPROTO=none ONBOOT=yes NETWORK=10.0.1.0 NETMASK=255.255.255.0 IPADDR=10.0.1.27 USERCTL=no

The values required in an interface configuration file can change based
on other values. For example, the ifcfg-eth0 file
for an interface using DHCP looks quite a bit different because IP
information is provided by the DHCP server:

DEVICE=eth0 BOOTPROTO=dhcp ONBOOT=yes

The Network Administration Tool[/b]
(redhat-config-network) is an easy way to make
changes to the various network interface configuration files (refer to the
chapter titled Network Configuration[/i] in the
Red Hat Enterprise Linux System Administration Guide[/i] for detailed instructions on using
this tool).
However, it is also possible to edit the configuration files for a given network
interface manually.
Below is a listing of the configurable parameters in an
Ethernet interface configuration file:
BOOTPROTO=<protocol>,
where <protocol> is
one of the following:
none ― No boot-time protocol should be used.

bootp ― The BOOTP protocol should be used.

dhcp ― The DHCP protocol should be used.

BROADCAST=<address>,
where <address> is
the broadcast address. This directive is deprecated.

DEVICE=<name>,
where <name>
is the name of the physical device (except for
dynamically-allocated PPP devices where it is the
logical name[/i]).

DHCP_HOSTNAME ― Only use this option if
the DHCP server requires the client to specify a hostname before
receiving an IP address. (The DHCP server daemon in Red Hat Enterprise Linux does not
support this feature.)
DNS{1,2}=<address>,
where
<address> is a
name server address to be placed in
/etc/resolv.conf if the
PEERDNS directive is set to
yes.

HWADDR=<MAC-address>,
where <MAC-address> is the hardware
address of the Ethernet device in the form
AA:BB:CC:DD:EE:FF. This directive is
useful for machines with multiple NICs to ensure that the interfaces
are assigned the correct device names regardless of the configured
load order for each NIC's module. This directive should
not[/i] be used in conjunction with
MACADDR.

IPADDR=<address>,
where <address> is
the IP address.

MACADDR=<MAC-address>,
where <MAC-address> is the hardware
address of the Ethernet device in the form
AA:BB:CC:DD:EE:FF. This directive is used
to assign a MAC address to an interface, overriding the one assigned
to the physical NIC. This directive should not[/i]
be used in conjunction with HWADDR.

MASTER=<bond-interface>,where
<bond-interface>
is the channel bonding interface to which the interface the Ethernet
interface is linked.
This directive is used in conjunction with the
SLAVE directive.
Refer to Section 8.2.3 Channel Bonding Interfaces
for more about channel bonding interfaces.
NETMASK=<mask>,
where <mask> is
the netmask value.

NETWORK=<address>,
where <address> is
the network address. This directive is deprecated.

ONBOOT=<answer>,
where <answer> is
one of the following:
yes ― This device should be activated at
boot-time.

no ― This device should not be activated
at boot-time.

PEERDNS=<answer>,
where <answer> is
one of the following:
yes ― Modify
/etc/resolv.conf if the DNS directive is
set. If using DHCP, then yes is the
default.

no ― Do not modify
/etc/resolv.conf.

SLAVE=<bond-interface>,where
<bond-interface> is
one of the following:
yes ― This device is controlled
by the channel bonding interface specified in the
MASTER directive.

no ― This device is
not[/i] controlled by the channel bonding
interface specified in the MASTER
directive.

This directive is used in conjunction with the
MASTER directive.
Refer to Section 8.2.3 Channel Bonding Interfaces
for more about channel bond interfaces.

SRCADDR=<address>,
where <address>
is the specified source IP address for outgoing packets.

USERCTL=<answer>,
where <answer> is
one of the following:
yes ― Non-root users are allowed to
control this device.

no ― Non-root users are not allowed to
control this device.