Oracle Telnet 1521 failed

Work found his computer "Telnet 127.0.0.1 1521" (Note: Do not spell telnet 127.0.0.1:1521) can be passed, but use localhost, host name to Telnet, then failed.

Workaround:

View port Status: CMD-> netstat-a-N

The results shown are: 1521 port corresponds to the local address bar: 127.0.0.0:1521,

At this point, modify the Dbhome_1\network\admin\listener.ora file under the Oracle installation directory (or plsql file instantclient_11_2\ The host value of Listener.ora), to 0.0.0.0.

Reboot the Oracle listening service;

Again through Netstat view port information, display: 1521 port corresponding to the local address bar: 0.0.0.0:1521

You can then telnet through the 127.0.0.1 or Loaclhost or host name or native IP.

"Oracle 11g--from Getting started to proficient" questions about Client Access: (P48)

After Oracle installation is complete under Windows system, open port 1521 (the Oracle default listening port) in its firewall settings. If the client is still inaccessible, further setup is required to add a registry key "Use_shared_socked" under Registry "HKEY_LOCAL_MACHINE"-"Software"-"ORACLE"-"home". and set the value to True, and then restart the Oracle Service and listener service.

Summarize:

Oracle Telnet 1521 failed, to check the following points:

1, whether the firewall is open, if open, whether there are 1521 ports open;

2, the Listener.ora file's host value.

Note: More than 10.2, Use_sharded_socket is already the default value of true, no need to modify.