[Technical Tips] How to set up static IP address on Debian

Step 1: Identify the Network Interface

Before configuring a static IP address, identify the network interface to be configured.
Open Terminal and enter the following command: ip link
The command lists all available network interfaces.

Locate the network interface with the status UP, LOWER_UP.
In this example, the network interface name is: enp0s8
Please verify the actual name based on your system.

Step 2 : Check the Current Network Information

Before configuring a static IP, check the current network settings assigned by DHCP.
Record the current IP address, gateway, and DNS server for reference.

• Check the IP Address
  Enter the following command: ip addr
  Find the IP address assigned to the network interface.
• Check the Gateway
  Enter the following command: ip route
  The default gateway is shown after default via.
• Check the DNS Server
  Enter the following command: cat /etc/resolv.conf
  You will typically see something like the following, where the IP address listed after “nameserver” is the DNS server currently in use. Record the current network information for the static IP configuration.
• Check the Network Configuration File
  Enter the following command: cat /etc/network/interfaces
  Review the current network interfaces and configuration before modifying the network settings.

Step 3: DHCP Reservation (Verification)

If DHCP Reservation is enabled on your network, no additional network configuration is required. Simply keep the network interface configured for DHCP.

Verification:

• Enter the following command: ip addr
• Restart the system two or three times.
• Verify that the same IP address is assigned after each reboot.

If the IP address remains the same after each reboot, DHCP Reservation is working correctly.

Step 4: Configure a Static IP Address (Without DHCP Reservation)

If your network does not support DHCP Reservation, configure a static IP address manually.

Open the network configuration file:

Locate the configuration for your network interface (for example, enp0s8). If a DHCP configuration already exists, comment it out, then add the following static IP configuration:

Note:

• Replace enp0s8 with your actual network interface name.
• Replace the IP address, gateway, subnet mask, and DNS server values according to your network environment.

Step 5 : Save the Configuration and Restart

After saving the configuration file, restart the system by running sudo reboot to apply the new network settings.

Step 6 : Verify the IP Configuration

After restarting the system, verify the IP address by running the following command: ip addr

If the displayed IP address matches the configured static IP address, the static IP configuration has been applied successfully.