You must set the ORACLE_HOSTNAME environment variable to install Oracle Database on a multialias computer. A multialias computer is one to which multiple aliases resolve.
A computer with multiple aliases is a computer that is registered with the naming service under a single IP address, but which resolves multiple aliases to that address. The naming service resolves any of those aliases to the same computer. Before installing Oracle Database on such a computer, set the Oracle installation owner environment variable ORACLE_HOSTNAME to the computer whose host name you want to use.