Learn in the textbookIP Addresses and the Address System
DefinitionA private IP address (プライベートIPアドレス) is an IP address used only inside an internal network, such as at home or in a company.
ExplanationYou pick from reserved ranges, such as the one starting with 192.168, and assign addresses so none repeats across the internal network. A private address cannot talk to the internet as it stands, so a function called NAT (Network Address Translation) converts between it and a global IP address.
AnalogyThink of an internal extension that works only inside a company. Another company can have the same extension without trouble, and outside calls connect through the main number.
Memory hookIt is the private of private room, so picture a number that does not reach beyond the room on its own.