[oracle@lunar ~]$ ss SQL*Plus: Release 10.2.0.1.0 - Production on Sun Nov 10 01:09:36 2013 Copyright (c) 1982, 2005, Oracle. All rights reserved. Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production With the Partitioning, OLAP and Data Mining options SYS@orcl>conn lunar/lunar@ora920 Connected. LUNAR@ora920>conn lunar/lunar@ora817 Connected. LUNAR@ora817>conn lunar/lunar@ora816 ERROR: ORA-03134: Connections to this server version are no longer supported. Warning: You are no longer connected to ORACLE. LUNAR@ora817>
可以看到，从10.2开始，还支持连接oracle 817的数据库，但是已经不支持连接到oracle 816的数据库了，查了下文档，内容如下：
[oracle@lunar admin]$ ss SQL*Plus: Release 9.2.0.4.0 - Production on Sun Nov 10 01:08:55 2013 Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved. Connected to: Oracle9i Enterprise Edition Release 9.2.0.4.0 - Production With the Partitioning option JServer Release 9.2.0.4.0 - Production SQL> conn lunar/lunar@ora816 Connected. SQL> conn lunar/lunar@ora817 Connected. SQL> conn lunar/lunar@ora920 Connected. SQL> conn lunar/lunar@ora102 Connected. SQL> [oracle@lunar admin]$ ss SQL*Plus: Release 8.1.6.0.0 - Production on Sun Nov 10 01:05:32 2013 (c) Copyright 1999 Oracle Corporation. All rights reserved. Connected to: Oracle8i Enterprise Edition Release 8.1.6.1.0 - Production With the Partitioning option JServer Release 8.1.6.0.0 - Production SQL> conn lunar/lunar Connected. SQL> conn lunar/lunar@ora102 Connected. SQL> conn lunar/lunar@ora920 Connected. SQL> conn lunar/lunar@ora817 Connected. SQL>
今天连接时遇到 TNS-12560: TNS:protocol adapter error，顺便说一下，这个问题比较常见，常见原因有几种：
1，防火墙设置问题，关闭防火墙（service iptables stop）
2，修改了/etc/hosts的ip地址后，需要重启listener
3，listener.log过大（新版本中这个问题好多了）
4，10g中有一个注明的bug，listener会启动一个子监听造成listener hang
5，tnsnames.ora中配置的ip地址等不对
。。。。。。。。。。。。。。。
