How to Configure an IPv4 Address in Linux Server

“Linux is only free if your time is worth nothing.”
Jamie Zawinski

Configure an IPv4 Address in Linux Server

Overview

This guide provides step-by-step instructions on how to configure an IPv4 address on various Linux distributions.

Prerequisites

Access to a Linux server (physical or virtual).
Root or sudo privileges.
Basic understanding of Linux command line.

Step 1: Identify Network Interface Name

First, you need to identify the network interface you want to configure. Run the following command:

ip link show

This command lists all network interfaces. Look for the interface name (e.g., eth0, ens33, etc.).

Step 2: Configure the IPv4 Address

To configure a static IPv4 address, you need to edit the network configuration files. The location and syntax of these files may vary depending on the Linux distribution.

1. Ubuntu/Debian (using Netplan)

For Ubuntu 17.10 and later, configurations are managed via Netplan:

sudo nano /etc/netplan/01-netcfg.yaml

Add the following lines to configure the static IP:

network:
    version: 2
    renderer: networkd
    ethernets:
        :
            dhcp4: no
            addresses:
              - /24
            gateway4: 
            nameservers:
                addresses:
                - 8.8.8.8
                - 8.8.4.4

Example:

network:
    version: 2
    renderer: networkd
    ethernets:
        ens33:
            dhcp4: no
            addresses:
              - 192.168.1.100/24
            gateway4: 192.168.1.1
            nameservers:
                addresses:
                - 8.8.8.8
                - 8.8.4.4

2. Ubuntu/Debian (using /etc/network/interfaces)

For older systems or to use the traditional method:

sudo nano /etc/network/interfaces

Add the following lines:

auto 
iface  inet static
    address 
    netmask 
    gateway 
    dns-nameservers

Example:

auto eth0
iface eth0 inet static
    address 192.168.1.100
    netmask 255.255.255.0
    gateway 192.168.1.1
    dns-nameservers 8.8.8.8 8.8.4.4

3. CentOS/RHEL/Fedora

Edit the configuration file for the specific network interface:

sudo nano /etc/sysconfig/network-scripts/ifcfg-

For Ubuntu/Debian (using /etc/network/interfaces)

sudo systemctl restart networking

For CentOS/RHEL/Fedora

sudo systemctl restart network

For Arch Linux

sudo systemctl restart systemd-networkd

Step 4: Verify the Configuration

Run the following command to verify your new IP address:

ip addr show

Check that the interface displays the new IP address you configured.

Summary

By following the steps in this guide, you will have successfully configured a static IPv4 address on your Linux server in various distributions. Always ensure your configuration is correct by verifying connectivity with tools like ping.

Note: Always back up configuration files before making changes and consult your network administrator if unsure about IP address assignments.