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Most modern LAN's use private IP ranges that are not visible on the Internet. This is due to the limited number of IPv4 addresses and the high cost of maintaining a block of public, registered IP addresses.
As a result, most LAN's LANs use NAT or Network Address Translation to access the Internet. Simply put, NAT takes a request from a private IP address and substitutes a public IP address for its transport across the Internet. When the response arrives, the original, private IP address is swapped back for its return to the requestor on the private LAN.
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