• For computers to communicate over networks, they need an identifier
• Across network segments, the standard identifier is an IP address
• IP addresses come in 2 varieties: IPv4 (32 bits) and IPv6 (128 bits)
• IPv4 addresses are often written like: 12.123.14.243
• IP addresses can be public, private, or local
• Public IP addresses should have one owner and identify one logical entity
• Private networks often share one of a few common ranges

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