uuid
iPXE> show uuid smbios/uuid:uuid = 86a9f546-d31b-4ba2-9bbb-303b61bcf8d1
iPXE> chain http://boot.ipxe.org/demo/boot.php?uuid=${uuid}
Contains the system UUID, which should be a globally unique and permanent identifier for the system. The system UUID is read from the SMBIOS information.
iPXE will normally send the system UUID as part of option 97 in all DHCP requests. If you need to prevent this, you can override the system UUID with an invalid value. For example:
iPXE> set uuid:string INVALID iPXE> dhcp # Option 97 will not be present in the DHCP request