Which IPv4 address range is reserved for private networks?

Which IPv4 address range is reserved for private networks?

• A. 10.0.0.0/8
• B. 172.0.0.0/8
• C. 192.0.2.0/24
• D. 203.0.113.0/24

Answer: (A)

Private IPv4 addresses are set aside for internal networks and aren’t routable on the public Internet. The address block 10.0.0.0/8 is dedicated to private use, meaning any address from 10.0.0.0 through 10.255.255.255 can be used within an organization without needing global uniqueness. The /8 subnet mask fixes the first octet at 10, leaving 24 bits for hosts within the private network. The other ranges listed aren’t private: 172.0.0.0/8 would span a much larger space than the private 172.x private range (private use there is actually 172.16.0.0/12 to 172.31.0.0/16); the remaining two are reserved for documentation and example networks, not for private addressing.

Private IPv4 addresses are set aside for internal networks and aren’t routable on the public Internet. The address block 10.0.0.0/8 is dedicated to private use, meaning any address from 10.0.0.0 through 10.255.255.255 can be used within an organization without needing global uniqueness. The /8 subnet mask fixes the first octet at 10, leaving 24 bits for hosts within the private network. The other ranges listed aren’t private: 172.0.0.0/8 would span a much larger space than the private 172.x private range (private use there is actually 172.16.0.0/12 to 172.31.0.0/16); the remaining two are reserved for documentation and example networks, not for private addressing.