Configuring an IP address is a fundamental task for network management and connectivity. In a Linux environment, this process is crucial for setting up servers, workstations, and other networked devices. This article will guide you through the steps to configure an IP address on a Linux system using both command-line tools and graphical interfaces. Understanding how to manage IP addresses in Linux can help ensure your network operates smoothly and efficiently.

Examples:

1. Using ifconfig (deprecated but still widely used):

   sudo ifconfig eth0 192.168.1.100 netmask 255.255.255.0 up

   This command assigns the IP address 192.168.1.100 with a subnet mask of 255.255.255.0 to the eth0 network interface and brings the interface up.

2. Using ip command (recommended):

   sudo ip addr add 192.168.1.100/24 dev eth0
   sudo ip link set dev eth0 up

   Here, 192.168.1.100/24 specifies the IP address and the subnet mask, and eth0 is the network interface.

3. Configuring a static IP address via /etc/network/interfaces (Debian/Ubuntu):

   Edit the file /etc/network/interfaces:

   sudo nano /etc/network/interfaces

   Add the following lines:

   auto eth0
   iface eth0 inet static
      address 192.168.1.100
      netmask 255.255.255.0
      gateway 192.168.1.1

   Save and close the file, then restart the networking service:

   sudo systemctl restart networking

4. Configuring a static IP address via netplan (Ubuntu 18.04 and later):

   Edit the netplan configuration file, usually located at /etc/netplan/01-netcfg.yaml:

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

   Add the following configuration:

   network:
    version: 2
    ethernets:
      eth0:
        dhcp4: no
        addresses: [192.168.1.100/24]
        gateway4: 192.168.1.1
        nameservers:
          addresses: [8.8.8.8, 8.8.4.4]

   Apply the configuration:

   sudo netplan apply

5. Using nmcli (NetworkManager CLI):

   sudo nmcli con add type ethernet ifname eth0 con-name static-eth0 ip4 192.168.1.100/24 gw4 192.168.1.1
   sudo nmcli con up static-eth0

   This creates a new connection named static-eth0 with the specified IP address and gateway, and then activates the connection.