How to Configure Static and Dynamic IP Addresses on Ubuntu, CentOS, and openSUSE

First, understand the concept of IP addresses.

IP Address Overview

Essential components for connecting a computer to the Internet: IP address + subnet mask + gateway + DNS IP address is the unique identifier for network access.

IPv4 address classes:

IPv4 addresses are divided into five classes A‑E; classes A, B, C are basic, while D and E are used for multicast and reserved purposes.

Special addresses:

0.0.0.0 – default route, e.g., ip route-static 0.0.0.0 0.0.0.0 10.10.10.1 255.255.255.255 – all hosts on the local subnet

127.0.0.1 – localhost, loopback address

224.0.0.1 – multicast address for all hosts

169.254.x.x – automatic IP assigned by Windows when DHCP fails

Private addresses: (used within enterprises, not routed on the Internet)

10.x.x.x

172.16.x.x – 172.31.x.x

192.168.x.x

1. Configuring IP on Ubuntu

1) Ubuntu versions before 18.04

# vi /etc/network/interfaces
auto enp10s0
iface enp10s0 inet static
address 192.168.1.2
netmask 255.255.255.0
gateway 192.168.1.1
dns-nameservers 114.114.114.114,8.8.8.8

# /etc/init.d/networking restart   # restart network

2) Ubuntu 18.04 and later

# vi /etc/netplan/50-cloud-init.yaml
network:
  version: 2
  renderer: networkd
  ethernets:
    enp10s0:
      dhcp4: no
      addresses: [192.168.1.3/24]
      gateway4: 192.168.1.1
      nameservers:
        addresses: [114.114.114.114,8.8.8.8]

# netplan try   # validate configuration
# netplan apply # apply without validation

If you prefer the older method, install the ifupdown package:

apt install ifupdown

2. Configuring IP on CentOS / Red Hat

1) CentOS/RedHat 5.x‑7.x

# vi /etc/sysconfig/network-scripits/ifcfg-eth0
DEVICE=eth0
ONBOOT=yes
TYPE=Ethernet
BOOTPROTO=static
IPADDR=192.168.1.4
NETMASK=255.255.255.0
GATEWAY=192.168.1.1
DNS1=114.114.114.114
DNS2=8.8.8.8

# service network restart   # restart network service

2) CentOS/RedHat 8.x

CentOS 8 is newer; use nmcli commands.

# Create static IP configuration for ens33
nmcli connection add type ethernet con-name ens33 ifname ens33 ipv4.addresses 192.168.1.5/24 ipv4.gateway 192.168.1.1 ipv4.method manual

# Create dynamic IP configuration for ens33
nmcli connection add type ethernet con-name ens33 ifname ens33 ipv4.method auto

# Modify IP non‑interactive
nmcli connection modify ens33 ipv4.addresses 192.168.1.6/24
nmcli connection up ens33

# Modify IP interactively
nmcli connection edit ens33
# then use the nmcli prompts to change the address, set method to manual, save and activate

# Show current configuration
nmcli

Note: From CentOS 8/RHEL 8 onward, the traditional network.service is deprecated; network configuration is managed by NetworkManager. To keep using the old service, install it with yum install network-scripts.

3. Configuring IP on openSUSE

# vi /etc/sysconfig/network/ifcfg-eth0
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=static
IPADDR=192.168.1.8
NETMASK=255.255.255.0
GATEWAY=192.168.1.1

# service network restart   # restart network

Conclusion

NetworkManager is a powerful tool for managing network settings across major Linux distributions, offering command‑line, text‑based, graphical, and web interfaces, with extensive parameters and broad compatibility.