When setting up a TCP/IP network, each machine on the network must be assigned a unique IP address.
Certain sets of IP address numbers are reserved for use in private networks. These numbers are made available so that if any network packets escape to the Internet, these numbers will be ignored so as not to cause a disruption.
These are the "Class C" network ranges and it's up to you to decide which range to use.
The most common ranges are 192.168.0.x and 192.168.1.x, where "x" is a different number for each machine.

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