Is there any way to find a FortiGate’s MAC address from its serial number?

Hi urushi,

Fortinet does not provide a documented public lookup that allows a FortiGate MAC address to be derived from its serial number, so what Fortinet Support advised is consistent with the available documentation.

If the FortiGate is still accessible, the MAC address can be obtained directly from the device with:

diagnose hardware deviceinfo nic <interface>

Fortinet documents this command and the Current_HWaddr and Permanent_HWaddr fields here:
FortiOS 8.0 — Displaying detailed Hardware NIC information

If the FortiGate is completely offline or inaccessible, I would instead check the surrounding infrastructure for previously learned information, such as the switch MAC/CAM table, ARP/DHCP records, or deployment documentation.

One additional consideration is HA: the MAC address observed on the network can be an HA virtual MAC rather than the physical MAC of an individual cluster member. Fortinet documents this distinction here:
FortiOS 7.6 — Cluster virtual MAC addresses

So, unfortunately, the serial number alone is not a reliable way to derive the MAC address. If the device cannot be accessed, the surrounding network infrastructure may be the best source for recovering the previously learned MAC address.

Hope this helps.

Hi ​@urushi 

It is not possible to get MAC address details from SN.

Each FGT interface has unique MAC address