Unable to connect when localhost is mentioned in listener.ora, but working fine when the ip address

Hi,

I have installed a 11g database on a windows server. In the listener.ora when the entry for host is given as localhost, the connection from the server itself is failing.

i.e. when trying to connect as sqlplus username/passwd@servicename

But when the ip address of the server is mentioned in listener.ora, it's working normal.

Is it must to mention the ip address in the listener.ora? Can't we run it by mentioning localhost.

If we want to run it by mentioning localhost, what should be the entry in listener.ora look like?

Regards,

Prasanna.