while trying to login into the oracle account , i was unable to login into the system resulting the message “oracle ora-12545 target host or object does not exist” .And i finally solved orac 12545 target host or object not found . How i solved this issue: Actually , orac 12545 target host or object not found problem was encountered when i tried to login into the database server from the client machine where client oracle was installed. I don’t think which files are created during the client oracle installation .But let me tell you that the listener.ora file will not be created during the client installation because listener.ora file contains the information to listen the request send by the client which clearly indicates that this file will be created in the oracle database server.