Operating system and syntax UNIX / Windows 
-H { host-name | localhost1  }
Use with Maximum value Minimum value Single-user default Multi-user default
CC, DBS, DS – – – –
host-name
The name (address) of the database server machine. This name is assigned to the machine in your TCP/IP hosts file.
localhost
A reserved word that specifies that the Database server communicates only with clients on the database server machine.

Use Host Name (-H) to identify the host name.

To allow a specific IP address or an alias as the value for the -H parameter, specify the -hostnameAliasing parameter on the command line. If you enable -hostnameAliasing, you can control which Network Interface Card (NIC) is used for network communication.

1 localhost does not apply to DataServers.