The Internet Assigned Numbers Authority (IANA) has reserved the following three blocks of IP address space for private networks.

10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.31.255.255
192.68.0.0 - 192.68.255.255

The first block is a single class A network number.

The second block is a set of contiguous class B network numbers.

The third block is a set of contiguous class C network numbers.

The examples used in these courses are based on these private addresses.
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