I have not worked a lot with Linux, but have worked on other UNIX operating systems for numerous years.
Does the server/host have a valid IP address or hostname other than the loopback IP? Do you have a default domain?
I would suggest not using the loopback IP as your host. Is there a hostname for the server or does it have a valid IP address? you can look in the /etc/hosts file. You can also find domain information in the file: /etc/resolv.conf
When these questions can be answered, I would modify the listener.ora file to have a valid host. Also, I would likewise change the tnsnames.ora file to use that same host. Since this is just a home setup, I doubt you have issues with your domain…. but just in case, here is an entry of a “fully qualified” database for the tnsnames.ora file: database SID= PROD domain= acme.com
(ADDRESS = (PROTOCOL = TCP)(HOST = prodserver.acme.com)(PORT = 1632))
(SERVICE_NAME = PROD.ACME.COM)
I hope this helps.