Linux 7 Configuring a Network Interface
External
Internal
Overview
The configuration files corresponding to the network interfaces are located in /etc/sysconfig/network-scripts.
ifcfg-eth0 example:
DEVICE=eth0
NAME=eth0
TYPE=Ethernet
ONBOOT=yes
BOOTPROTO=none
IPADDR=192.168.1.9
NETMASK=255.255.255.0
PREFIX=24
GATEWAY=192.168.1.1
DNS1=8.8.8.8
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=no
IPV6_AUTOCONF=no
IPV6_DEFROUTE=no
IPV6_FAILURE_FATAL=no
IPV6_PEERDNS=no
IPV6_PEERROUTES=no
IPV6_PRIVACY=no
Configuration
DEVICE
IPADDR
NETMASK
PREFIX
GATEWAY
UUID
An unique ID for the interface.
A unique value can be created with uuidgen
HWADDR
Specifying the hardware or MAC address using the HWADDR directive will influence the device naming procedure.
DEFROUTE
Change the IP Address
Modify/verify the following set of variables. Make sure the hardware address is correct.
DEVICE=eth0 HWADDR="08:00:27:0A:79:9F" IPADDR="172.20.1.3" PREFIX="16" NETMASK="255.255.0.0" GATEWAY="172.20.1.1"
Note that this is how a static address is changes even if NetworkManager is active.
Configure a Network Interface after Cloning a VM Image
In general, when cloning a system, you want to generated a different Mac address when cloning an image, to avoid collisions.
If "HWADDR" is set pointing to the old hardware address, we want to remove it from the cloned configuration file, because if it stays there, and the hardware address is not available, the interface won't start.
Change the UUID
Use uuidgen and replace the value from the the ifcfg-* file.