The video tutorial explains Network Address Translation (NAT), a method to provide Internet access to devices with private IP addresses. It covers different types of NAT, including static and dynamic NAT, and Port Address Translation (PAT). The tutorial also distinguishes between source NAT, which translates the source IP address, and destination NAT, which translates the destination IP address. It highlights that both source and destination NAT can be applied simultaneously to facilitate communication between local networks and the outside world.

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