as discussed in https://community.sophos.com/products/unified-threat-management/astaroorg/f/80/t/64830 you can filter MAC addresses by selecting a MAC address list (in the "Advanced" section within a firewall rule). Such MAC address lists can be defined in "Definitions & Users"->"Network Definitions"->"MAC Address Definitions". There you can import MAC lists, add a single MAC address or add Network-Host objects.
as discussed in https://community.sophos.com/products/unified-threat-management/astaroorg/f/80/t/64830 you can filter MAC addresses by selecting a MAC address list (in the "Advanced" section within a firewall rule). Such MAC address lists can be defined in "Definitions & Users"->"Network Definitions"->"MAC Address Definitions". There you can import MAC lists, add a single MAC address or add Network-Host objects.