DHCP Server Configurations

A FortiGate interface can host a DHCP server that automatically assigns IP addresses to connected devices. You can establish multiple DHCP servers on any interface, customizing settings like IP address range allocation, subnet mask, default gateway (usually the interface IP), and DNS server (typically FortiGate's DNS server).

DHCP Server Features in FortiGate

FortiGate's DHCP server simplifies network management with the following features:

Automatic IP Assignment: Automatically assigns IP addresses to devices.
IP Range Management: Defines specific IP address ranges for efficient use.
Subnet Mask Configuration: Ensures proper network segmentation.
Default Gateway & DNS Settings: Provides essential network settings automatically.
Lease Time Management: Controls IP address lease duration.
Device Detection: Monitors and identifies connected devices for enhanced security.
Multiple Interfaces Support: Configures DHCP on multiple network interfaces.
Custom Options: Allows setting custom DHCP parameters for specific needs.

How to Configure a DHCP Server

Configuring a DHCP (Dynamic Host Configuration Protocol) server on your FortiGate device automates IP address assignment and network configuration. Follow these steps to set up a DHCP server:

Access the FortiGate Interface:
- Log in to your FortiGate device's web-based interface using your browser.
Navigate to the Network Interfaces Section:
- Go to Network > Interfaces.
Select the Interface for DHCP Configuration:
- Click on the interface (e.g., port2) you want to configure as the DHCP server.
Enable DHCP Server:
- In the interface settings, check the box to Enable DHCP Server.
Configure DHCP Server Settings:
- IP Range: Specify the range of IP addresses that the DHCP server can assign (e.g., 192.168.1.100 to 192.168.1.200).
- Subnet Mask: Enter the subnet mask for the network (e.g., 255.255.255.0).
- Default Gateway: Enter the IP address of the default gateway (usually the IP address of the FortiGate interface, e.g., 192.168.1.1).
- DNS Server: Enter the IP address of the DNS server (e.g., 8.8.8.8 for Google DNS).
- Lease Time: Set the lease time for IP addresses (e.g., 86400 seconds for 24 hours).
Enable Device Detection:
- Optionally, enable Device Detection under the interface settings to allow the FortiGate to identify and monitor devices connecting to this interface.
Save the Configuration:
- Click OK or Save to apply the DHCP server settings.
Verify the DHCP Server:
- Go to Network > DHCP Monitor to ensure the DHCP server is active and assigning IP addresses to devices correctly.

Example Configuration:

IP Range: 192.168.1.100 - 192.168.1.200
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.1.1
DNS Server: 8.8.8.8
Lease Time: 86400 seconds

By following these steps, you can easily set up a DHCP server on your FortiGate device to manage IP address assignments efficiently.