Network Interface Tap
The Network Interface Tap (NIT) provided in SunOS release 4 is no longer required. Now Ethernet drivers are real STREAMS drivers that can be opened and communicated with directly.
See pfmod(7M), bufmod(7M), and dlpi(7P)
The Solaris 7 Ethernet drivers and other data link drivers support the connectionless Data Link Provider Interface (DLPI) Version 2 specification.