configuration.yaml
....
device_tracker:
  - platform: snmp
    host: 192.168.X.X
    community: public
    baseoid: 1.3.6.1.4.1.14988.1.1.1.2.1.1
    consider_home: 360
    track_new_devices: False
....    
    
known_devices.yaml
Krzysiek_3T:
  name: Krzysiek
  mac: 00:EE:00:00:00:00
  track: yes
  hide_if_away: no