Is there a way in the firewall to filter by a MAC address range? Say all the MAC addresses owned by Company X?
At some locations in the config, like the ACL, one indeed can specify MAC/subnet, see for example
https://wiki.mikrotik.com/wiki/Manual:CRS3xx_series_switches#Port_Security
/interface ethernet switch rule
add ports=ether1 src-mac-address=64:D1:54:81:EF:8E/FF:FF:FF:FF:FF:FF switch=switch1
add new-dst-ports=“” ports=ether1 switch=switch1
>