The agent of a Classic device is reachable and transmits packets with the basic MAC address printed on a label on the chassis and displayed in GUI and CLI.
The numerically first port gets as port MAC address the basic MAC address + 8. The other ports get the respective addresses in consecutive order.

Example:
Basic MAC: 00:11:22:33:44:00
1st port:      00:11:22:33:44:08
3rd port:      00:11:22:33:44:0A