linux Ethernet Interfaces

interface les is ifcfg-eth0, which controls the rst Ethernet network interface
card or NIC in the system. In a system with multiple NICs, there are multiple ifcfg-eth
Because each device has its own conguration le, an administrator can control how each interface functions individually. Below is a sample ifcfg-eth0 le for a system using a xed 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 conguration le can change based on other values. For example, the ifcfg-eth0 le 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 (redhat-config-network) is an easy way to make changes to
the various network interface conguration les (see the chapter titled Network Conguration in the
Red Hat Linux Customization Guide for detailed instructions on using this tool).
However, it is also possible to edit the conguration les for a given network interface by hand.
Below is a listing of the congurable parameters in an Ethernet interface conguration 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.
is the name of the physical device (except for dynamicallyallocated PPP devices where it is the logical name) is a name server address to be placed in
/etc/resolv.conf if the PEERDNS directive is set to yes.