APIPA Automatic Private IP addresses

169.254.x.x
When DHCP is unavailable

Public vs Private

Class A
IP 10.0.0.0 - 10.255.255.255
SM 255.0.0.0 ( /8 )

Class B
IP 172.16.0.0 - 173.31.255.255
SM 255.240.0.0 ( /12 )

Class C
IP 192.168.0.0 - 1982.168.255.255
SM 255.255.0.0 ( /16 )