Technical Tip: How to set DHCP IP reservation on FortiGate’s interface

The MAC address of the device for which an IP address has to be allocated must be known in order to make the reservation. After ensuring the availability of the information, follow these steps to make a reservation:

From the GUI:

1. Log in to the FortiGate.
2. Select Network to expand the menu.
3. Edit the interface for which the reservation must be assigned.
4. Go to the DHCP Server settings and select Advanced.

5. Select IP Address Assignment Rules.
6. To add an entry, select Create New and then input the necessary information fields for the reservation, such as MAC address and IP address. Select OK and Apply.
   
   

Note:

While adding the MAC address, the format to input is xx:xx:xx:xx:xx:xx and not xx-xx-xx-xx-xx-xx.

From the CLI:

config system dhcp server

edit 1

set dns-service default

set default-gateway 192.168.1.99

set netmask 255.255.255.0

set interface "lan"

config ip-range

edit 1

set start-ip 192.168.1.110

set end-ip 192.168.1.210

next

end

config reserved-address

edit 1

set ip 192.168.1.9

set mac c0:25:xx:xx:xx:xx

next

end

next

end

For the devices that have already learned the IPs via DHCP, IP reservation can be done via GUI by selecting the option 'Add from DHCP Client List' under the IP address Assignment Rules.