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The Internet Protocol (IP) delivers mail based on the specific email address. The domain of the address is expressed as four numbers, separated by periods (called dots), such as 163.52.128.72. However, because it would be difficult to remember such complex addresses, you can instead use Internet addresses made up of words, letters, and numbers. Computers called domain name servers translate the alphanumeric address into a numerical address, so email can be sent to the proper location.