- Public IP addresses are addresses that are valid as nodes on the Internet.
- They can be resolved and routed across the Internet from one point to another.
- Unlike public IP, private IP addresses are not valid on the Internet.
Three range of private IP addresses has been selected for the three network class.
For Class A network, 10.0.0.0 – 10.255.255.255 (10/8 prefix) range (For big network that requires a huge pool of 16 million private IP addresses)
For Class B network, 172.16.0.0 – 172.31.255.255 (172.16/12 prefix) range (For medium-sized network that requires 65000 private IP addresses)
For Class C network, 192.168.0.0 – 192.168.255.255 (192.168/16 prefix) range (Commonly used IP range on smaller network for easier addressing of 254 IP addresses. May not necessarily be smaller network but network managed in smaller blocks.)
Beside these, there is Microsoft’s 169.254.0.0 range of default IP addresses that are allocated to systems when they are unable to obtain address from a DHCP server. Its Called APIPA
When a DHCP server fails, APIPA allocates IP addresses in the private range 169.254.0.1 to 169.254.255.254.