.DUID File Extension

In version 6 of DHCP, both clients and servers are assigned DHCP Unique Identifiers (DUIDs). Devices use these IDs to identify themselves when connecting over a network that uses the DHCPv6 protocol. Servers can also use a client's DUID to pass options to only that client or prohibit that client from receiving any parameters.

NOTE: A device's DUID is sometimes saved in a file whose name ends in duid and does not include a file extension.

You can open a DUID file and view the UUID it contains in Microsoft Notepad (Windows), Apple TextEdit (Mac), or any other text editor.