NAT stands for Network Address Translation. NAT is a technique used to connect networks together, it is typically used when a device on a private network wants to communicate with a device on a public network, such as the internet. NAT operates on a router, which is responsible for replacing the private IP addresses of devices in a local network with a single public IP address, this allows multiple devices to share a single internet connection while keeping their private IP addresses hidden.

NAT is a way to assign multiple devices on a private network to a single public IP address, this is important because there are a limited number of IP addresses available on the internet, and NAT allows organizations to share a single IP address among multiple devices, saving IP addresses and preserving them for future use.

NAT can also be used for security reasons, by keeping the internal IP addresses hidden from the public internet. NAT can be configured in different ways, some of the most common uses are for port forwarding, which allows remote access to devices on a private network, for creating virtual private networks (VPNs), and for load balancing, which distributes network traffic among multiple devices.

DNS (Domain Name System) is a service that facilitates the association of domain names with their corresponding IP addresses. It eliminates the need for users to remember numerical IP addresses by translating domain names into IP addresses. When a user types a domain name into their browser, the browser sends a request to the DNS server which then resolves the domain name to the corresponding IP address that the website is hosted on. The DNS servers are organized in a hierarchical manner, with the root servers at the top, and the individual domains branching out from there. 

Difference between Network Address Translation (NAT) and Domain Name System (DNS)