Reformat a MAC address into the requested notation (colon, hyphen, Cisco dot or bare) and case (lower default or upper).

Generate a random EUI-48 MAC address. By default it is locally-administered and unicast (safe for testing); set `local:false` for a universal-bit address or `multicast:true` for a group address.

Report the properties of a MAC address encoded in its first octet: unicast vs multicast (I/G bit), universal vs locally-administered (U/L bit), the broadcast address, and — for EUI-48 — the OUI and NIC portions.

Parse a MAC / EUI-48 or EUI-64 address from any common notation (colon, hyphen, Cisco dot, or bare hex) and return it in every canonical form plus its integer value.

Derive the modified EUI-64 interface identifier from a 48-bit MAC (insert FFFE, flip the U/L bit) and the resulting IPv6 link-local address (fe80::/64).