[or DottedQuad]
Internet Address is a number assigned to a NetworkInterfaceCard. The form either in the InternetProtocolVersionFour dotted octet quartet format: 127.0.0.1, or in the InternetProtocolVersionSix format: ::1. Any octet cannot be greater than 255 because these numbers represent a 32 bit binary number which is actually the version 4 InternetAddress. A version 6 InternetAddress uses HexaDecimal notation and is 128 bits long. DomainNameServers provide a database like service that matches each InternetAddress to a name. These names are registered with various entities that charge money to lease the name.
This is addressed from PortForwarding.
The addresses 127.0.0.1 and ::1 are also known as the special LocalHost, because it always refers to the computer you are using at the time.