Network Host and Domain Names

The hostid parameter is an integer that identifies the host machine.

Host IDs fall under the category of Internet network addressing because, by convention, the 32-bit Internet address is used. The socket subroutines that manage the host ID are:
Socket subroutines to manage the internal host name are:
When a site obtains authority for part of the domain name space, it invents a string that identifies its piece of the space and uses that string as the name of the domain. To manage the domain name, applications can use the following socket subroutines: