按照网上的教程，修改了sqlnet.ora

NAMES.DIRECTORY_PATH= (TNSNAMES, ONAMES, HOSTNAME)
SQLNET.ALLOWED_LOGON_VERSION_SERVER=11;
SQLNET.ALLOWED_LOGON_VERSION_SERVER=12;
SQLNET.ALLOWED_LOGON_VERSION_CLIENT=11;
SQLNET.ALLOWED_LOGON_VERSION_CLIENT=12;

就是因为这个配置，然后就出现Ora-12514了。

startup的时候提示：

ORA-01012: not logged on

查看监听状态会提示：


instance status blocked


需要按照地址：https://www.cnblogs.com/ios9/p/8078977.html 教程关掉oracle


[oracle@localhost ~]$ kill oracle
 23 -bash: kill: oracle: arguments must be process or job IDs
 24 [oracle@localhost ~]$ ps -ef|grep ora_dbw0_$ORACLE_SID
 25 oracle    4619     1  0 Dec20 ?        00:00:37 ora_dbw0_orcl
 26 oracle   11382 10996  0 09:47 pts/3    00:00:00 grep ora_dbw0_orcl
 27 [oracle@localhost ~]$ kill -9 4619
 28 [oracle@localhost ~]$ kill 10996
 29 [oracle@localhost ~]$ ps -ef|grep ora_dbw0_$ORACLE_SID
 30 oracle   11386 10996  0 09:47 pts/3    00:00:00 grep ora_dbw0_orcl

启动还是不行，最后把sqlnet.ora该回去，注释掉部分不要的，正确配置如下：

# sqlnet.ora Network Configuration File: /opt/oracle/product/18c/dbhome_1/network/admin/sqlnet.ora
# Generated by Oracle configuration tools.

NAMES.DIRECTORY_PATH= (TNSNAMES, ONAMES, HOSTNAME)
#SQLNET.ALLOWED_LOGON_VERSION_SERVER=11;
#SQLNET.ALLOWED_LOGON_VERSION_SERVER=12;
#SQLNET.ALLOWED_LOGON_VERSION_SERVER=18;
SQLNET.ALLOWED_LOGON_VERSION_CLIENT=11;
SQLNET.ALLOWED_LOGON_VERSION_CLIENT=12;
SQLNET.ALLOWED_LOGON_VERSION_CLIENT=18;

startup数据库，终于起来了。再重启监听就好了。