Connection Manager and ORA-12529
A simple configuration with Oracle Connection Manager (CMAN) did not work, I constantly received ORA-12529 when trying to connect with sqlplus to a database through CMAN. After checking cman.ora over and over and browsing all the trace files I finaly dived into one and found a problem with host name resolving. Turned out that the host name defined in /etc/hosts on the database server was not known outside the server. The database, I assume, did a lookup on the ip number in local /etc/hosts and sent the host name to CMAN when registering. The fact that I had used ip-numbers in the local listener.ora and tnsnames.ora did not change that behavior. A properly DNS would have saved me this, the solution was to define the database server name in local host file on server where CMAN is running. ...