How to Set Up and Configure a DHCP Server on Ubuntu Server

Why Run a DHCP Server on Ubuntu?

The Dynamic Host Configuration Protocol (DHCP) automatically assigns IP addresses and network configuration parameters to devices on a network. While many routers have built-in DHCP functionality, running a dedicated DHCP server on Ubuntu Server provides significantly more control, advanced logging, and scalability for complex network environments.

Step 1: Install the isc-dhcp-server Package

Log in to your Ubuntu Server and update your package list. Then, install the DHCP server package by running the following commands in your terminal:

sudo apt update
sudo apt install isc-dhcp-server -y

Step 2: Define the Network Interface

You must tell the DHCP server which network interface to listen on. Open the default configuration file in a text editor:

sudo nano /etc/default/isc-dhcp-server

Locate the INTERFACESv4 line and add your network interface name (e.g., eth0 or enp3s0). You can find your interface name using the ip a command.

INTERFACESv4="eth0"

Step 3: Configure the DHCP Pool

Next, configure the IP address pool and network settings. Open the main DHCP configuration file:

sudo nano /etc/dhcp/dhcpd.conf

Scroll to the bottom of the file and add your subnet configuration:

subnet 192.168.1.0 netmask 255.255.255.0 {
  range 192.168.1.100 192.168.1.200;
  option routers 192.168.1.1;
  option domain-name-servers 8.8.8.8, 8.8.4.4;
  default-lease-time 600;
  max-lease-time 7200;
}

Step 4: Restart and Enable the Service

Save the file and exit the editor. Restart the DHCP service to apply your new configuration, and enable it to start automatically on boot:

sudo systemctl restart isc-dhcp-server
sudo systemctl enable isc-dhcp-server

Step 5: Verify the Service Status

Ensure the service is running without errors by checking its status:

sudo systemctl status isc-dhcp-server

If the service is active (running), your Ubuntu server is now successfully assigning IP addresses to client devices on the network.