Defines the classification level byte to use in the default label
associated with a not-yet-labelled outbound datagram.
IP_NWIF_LEVEL_UNCLASSIFIED 171 0x000000AB
IP_NWIF_LEVEL_CONFIDENTIAL 150 0x00000096
IP_NWIF_LEVEL_SECRET 90 0x0000005A
IP_NWIF_LEVEL_TOPSECRET 61 0x0000003D