Oracle Database will typically initialize and running on the default ip address and port: 1521. However, since this is pretty common knowledge you may wish to change up the ports and/or ip address to force it listen somewhere else.

1) Modify the TNSNAMES.ora file to listen to the specific address and port that you want:
{DBNAME}=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST={IPADDRESS})(PORT={PORT})))(CONNECT_DATA=(SERVER=DEDICATED)(SID={ORACLE_SID})))

2) Modify (create) the LISTENER.ora file to listen to the specific address and port that you want:
my_listener=(DESCRIPTION_LIST=(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST={IPADDRESS})(PORT={PORT}))(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1522))))

3) Add the following line to the init{ORACLE_SID}.ora file to force it to listen:
LOCAL_LISTENER='(ADDRESS=(PROTOCOL=TCP)(HOST={IPADDRESS})(PORT={PORT}))’

Replace the {DBNAME}, {ORACLE_SID}, {IPADDRESS} and {PORT} variables. NOTE: this is just an example you may need to tweak this a bit for your specific environment. Restart the database and listener and you should be good to go! Not make sure that your firewall knows about the change otherwise you may cause things to break!