The Domain System Network software generally needs a 32-bit Internet address in order to open a connection or send a datagram. However users prefer to deal with computer names rather than numbers. Thus there is a database that allows the software to look up a name and find the corresponding number. When the Internet was small, this was easy. Each system would have a file that listed all of the other systems, giving both their …showed first 75 words of 778 total…

…showed last 75 words of 778 total…utilities will talk to a server on their own system. This server will take care of contacting the other servers for them. This keeps down the amount of code that has to be in each application program. The domain system is particularly important for handling computer mail. There are entry types to define what computer handles mail for a given name, to specify where an individual is to receive mail, and to define mailing lists.