(B-NET) Top level Unix Ethernet software developed at the University of California at Berkeley. There are no formal specifications but UCB's 4.2BSD Unix implementation on the VAX is the de facto standard. Distributed by Unisoft. Includes net.o driver routines for specific hardware, pseudo ttys, daemons, hostname command to set/get name, /etc/hosts database of names and Internet addresses of other hosts, /etc/hosts.equiv host-wide database to control remote access, .rhosts per user version of hosts.equiv.

UCB's implementation of the Internet Protocol includes trailers to improve performance on paged memory management systems such as VAXen. These trailers are an exception to the Internet Protocol specification.