One is the older standard for identifying systems on a network and is only maintained for backwards compatibility on Microsoft networks. If you want someone to tell you what is good and bad about DNS then I think you are better off doing your own research on wikipedia about it. Nobody here will be able to tell you that information. DNS is centralized name and IP resolution on Microsoft networks. It is an essential service on all enterprise networks. Home a domain controller that is also managing DNS like you will find in enterprise networks.. Home routers are responsible for DNS on home networks.