How to configure virtual network interface on Redhat 7 Linux

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The following config will help you to configure a virtual network interface to allow you to have multiple additional network IP address on a single hardware network interface. For example our RHEL server has currently a single hardware network interface called eth0. This interface is used as a master network interface with an IP address of 10.1.1.110. To this network interface we will attach two additional virtual network interfaces eth0:0 - 10.1.1.111 and eth0:1 - 10.1.1.112. Let’s get started by showing a current network configuration:

[root@rhel7 ~]# ip addr show

Show network configuration on RHEL7 linux

From the above output we can see that currently we have configured eth0 network interface only. Next, we are going to locate a corresponding network interface configuration file for eth0:

# grep -l DEVICE.*eth0 /etc/sysconfig/network-scripts/*

Show network configuration file on RHEL7 linux

The configuration file responsible for the eth0 network interface is /etc/sysconfig/network-scripts/ifcfg-eth0

[root@rhel7 ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0 
DEVICE="eth0"
NETBOOT="yes"
HWADDR="08:00:27:15:38:B7"
TYPE="Ethernet"
BOOTPROTO="none"
NAME="eth0"
UUID="462f4834-4fe7-43a7-84e7-83b2722e94c1"
ONBOOT="yes"
IPADDR="10.1.1.110"
NETMASK="255.0.0.0"
GATEWAY="10.1.1.1"

In order to create a virtual network interface we can first copy a master configuration file /etc/sysconfig/network-scripts/ifcfg-eth0 and then edit its content to set an appropriate network interface name and IP address:

[root@rhel7 ~]# cd /etc/sysconfig/network-scripts/
[root@rhel7 ~]# cp ifcfg-eth0 ifcfg-eth0:0
[root@rhel7 ~]# cp ifcfg-eth0 ifcfg-eth0:1

Next, we need to edit DEVICE, NAME, IPADDR in both virtual network configuration files. Below you can see both edited configuration files:

# cat /etc/sysconfig/network-scripts/ifcfg-eth0:0 
DEVICE="eth0:0"
NETBOOT="yes"
HWADDR="08:00:27:15:38:B7"
TYPE="Ethernet"
BOOTPROTO="none"
NAME="eth0:0"
UUID="462f4834-4fe7-43a7-84e7-83b2722e94c1"
ONBOOT="yes"
IPADDR="10.1.1.111"
NETMASK="255.0.0.0"
GATEWAY="10.1.1.1"

and

# cat /etc/sysconfig/network-scripts/ifcfg-eth0:1 
DEVICE="eth0:1"
NETBOOT="yes"
HWADDR="08:00:27:15:38:B7"
TYPE="Ethernet"
BOOTPROTO="none"
NAME="eth0:1"
UUID="462f4834-4fe7-43a7-84e7-83b2722e94c1"
ONBOOT="yes"
IPADDR="10.1.1.112"
NETMASK="255.0.0.0"
GATEWAY="10.1.1.1"

Once you have edited the additional virtual network interface files, all needs to be done is to restart your network. On RHEL7 linux server this can be achieved by:

[root@rhel7 ~]# systemctl restart network

Next, check your network settings again and look for two additional virtual network interfaces:

[root@rhel7 ~]# ip addr show

Show virtual network interfaces on RHEL7 linux

As a last and optional step you can test your newly configured virtual network interface with a ping command from some other host on your network:
Ping/Test virtual network interfaces on RHEL7 linux

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