Classfull IPv4
Table 12-2 IPv4 Address Classes Based on First Octet Values
Class First Octet Values Purpose
A 1–126 Unicast (large networks)
B 128–191 Unicast (medium-sized networks)
C 192–223 Unicast (small networks)
D 224–239 Multicast
E 240–255 Reserved (formerly experimental)
address ranges of all addresses that begin with 0 and all addresses that begin with 127 are reserved