A little greppage finds that class A network 127 is marked as Reserved in RFCs 790. 820, 870, 900, 923, 943, and 960. It is Loopback in RFCs 990, 997, and later ones. The word loopback appears in other contexts in earlier RFCs but the first application to IP I can find is in RFC 990 in 1986. R's, John