[oracle@prod ~]$ oerr ora 28547
28547, 0000, "connection to server failed, probable Oracle Net admin error"
// *Cause: A failure occurred during initialization of a network connection
// from a client process to the Oracle server. The connection
// was completed but a disconnect occurred while trying to
// perform protocol-specific initialization, usually due to
// use of different network protocols by opposite sides
// of the connection. This usually is caused by incorrect
// Oracle Net administrative setup for database links or external
// procedure calls. The most frequent specific causes are:
// -- The connection uses a connect string which refers
// to a Heterogeneous Services agent instead of
// an Oracle server.
// -- The connection uses a connect string which includes
// an (HS=) specification.
// -- Hitting Ctrl+C before connection initialization is
// complete.
// -- Using DRCP on Windows with SQLNET.AUTHENTICATION_SERVICES
// set to NTS.
// -- Connection timeout due to SQLNET.INBOUND_CONNECT_TIMEOUT
// parameter when all shared servers are busy in
// shared server configuration.
// *Action: Check Oracle Net administration in the following ways:
// -- When using TNSNAMES.ORA or an Oracle Names server, make sure
// that the client connection to the Oracle server uses
// the correct service name or SID.
// -- Check LISTENER.ORA on the connection end point's host machine
// to assure that this service name or SID refers
// to the correct server.
// -- Confirm in TNSNAMES.ORA or the equivalent service definition
// that the connect string does not contain (HS=).
// -- Set SQLNET.AUTHENTICATION_SERVICES to NONE when using DRCP
// on Windows.
//
首先保证你的数据库已经启动了。
然后启动plsql developer
如图，你按照这种直接连接的方式填写database那一栏试一下，格式如下：
ip:端口号/sid
例如上图，
192.168.100.167是oracle服务器的ip地址
1521是监听器的端口号
orcl是oracle数据库的sid
如果这样可以连接，拿就是你的tnsnames.ora文件配置的问题了。
