How to: Use a Sophos XG as a DHCP Server

Dynamic Host Configuration Protocol (DHCP) is a vital service that simplifies network management by automatically assigning IP addresses and other network configuration parameters to devices on the network. By setting up DHCP scope on a Sophos XG Firewall, you can efficiently manage IP address allocation and ensure seamless connectivity for devices within your organization.

This step-by-step guide will walk you through the process of configuring DHCP scope on a Sophos XG Firewall. By following these steps, you can establish an organized and efficient DHCP service to support your network’s IP address management requirements.

Step 1: Access the Management Interface

Begin by accessing the Sophos XG Firewall’s web-based management interface:

1. Open a web browser on a computer connected to the same network as the Sophos XG Firewall.
2. Enter the IP address assigned to the LAN (Internal) interface of the Sophos XG Firewall in the browser’s address bar and press “Enter.”
3. Enter the administrative username and password to log in to the management interface.

Step 2: Navigate to DHCP Settings

In the management interface, navigate to the DHCP settings to configure the DHCP scope:

1. Click on “Networking” in the top menu.
2. Select “DHCP” from the drop-down menu and click on “Server Options.”

Step 3: Add a New DHCP Scope

Create a new DHCP scope to define the IP address range and other configuration parameters:

1. Click “Add” to create a new DHCP scope.
2. Enter a descriptive name for the DHCP scope (e.g., LAN-Scope).
3. Specify the IP address range to be used for DHCP clients. Enter the starting and ending IP addresses.
4. Set the subnet mask to define the size of the network segment.
5. Configure the lease duration, which determines how long IP addresses are leased to DHCP clients.

Step 4: Configure Additional DHCP Options

Define additional DHCP options based on your network requirements:

1. Click on the “Additional Options” tab within the DHCP scope configuration.
2. Add any specific DHCP options, such as default gateway, DNS servers, WINS servers, or domain name.
3. Specify the values for each DHCP option based on your network configuration.

Step 5: Save and Apply DHCP Scope

Review the DHCP scope settings and save the changes:

1. Click “Save” to create the DHCP scope.
2. Apply the changes to activate the DHCP scope on the Sophos XG Firewall.

Step 6: Monitor and Manage DHCP Clients

After configuring the DHCP scope, monitor and manage DHCP clients:

1. In the DHCP server options, navigate to the “Lease Information” tab to view the list of active DHCP leases and their expiration times.
2. Inspect the DHCP lease information to identify the connected devices and their assigned IP addresses.
3. If necessary, you can manually release or renew DHCP leases for specific devices.

Conclusion:

Setting up DHCP scope on a Sophos XG Firewall streamlines network management and ensures efficient IP address allocation for connected devices. By following this step-by-step guide, you have successfully configured a DHCP scope, defined DHCP options, and monitored DHCP clients on the Sophos XG Firewall. With DHCP scope in place, your organization can maintain a well-organized and reliable network environment, providing seamless connectivity for all devices.