Network Configuration After CentOS Minimal Installation

Getting Started

After installing CentOS minimal, the ifconfig command may not exist.

[root@localhost home]# ifconfig
bash: ifconfig: command not found

When checking the IP address with ip addr, the IP address may also not be assigned. This happens because the network has not been configured yet.

Configuring the NIC

First, switch to the root account and move to /etc/sysconfig/network-scripts. Then check the files.

cd /etc/sysconfig/network-scripts/
ls ifcfg*

The ifcfg-eth0 file contains the NIC configuration. The name eth0 can differ depending on the environment.

Dynamic Address

Change ONBOOT=no to ONBOOT=yes to enable DHCP.

Static Address

To use a static address, change BOOTPROTO=dhcp to BOOTPROTO=static and add values such as the following.

IPADDR=192.168.100.123
NETMASK=255.255.255.0
GATEWAY=192.168.100.1
DNS1=168.126.63.1
DNS2=168.126.63.2

Restarting the Network Service

Restart the network service.

service network restart
ip addr show

If configured correctly, the interface will show an assigned IP address.

Installing Network Tools

After confirming connectivity, install network tools to use ifconfig.

yum install net-tools

net-tools is a collection of basic networking utilities. Modern Linux systems often use replacement commands such as ip addr instead of ifconfig, ip route instead of route, and ip neigh instead of arp.