服务端监听状态：

lsnrctl status
LSNRCTL for Linux: Version 11.1.0.7.0 - Production on 04-AUG-2020 17:46:55
Copyright © 1991, 2008, Oracle. All rights reserved.
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
STATUS of the LISTENER

Alias LISTENER_VGAPPDB2
Version TNSLSNR for Linux: Version 11.1.0.7.0 - Production
Start Date 28-MAY-2020 10:34:32
Uptime 68 days 7 hr. 12 min. 23 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /oracle/product/11.1.0_1/network/adminstener.ora
Listener Log File /oracle/diag/tnslsnrgappdb2stener_vgappdb2/alert/log.xml
Listening Endpoints Summary…
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.101.102)(PORT=1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.101.13)(PORT=1521)))
Services Summary…
Service “+ASM” has 1 instance(s).
Instance “+ASM2”, status READY, has 1 handler(s) for this service…
Service “+ASM_XPT” has 1 instance(s).
Instance “+ASM2”, status READY, has 1 handler(s) for this service…
Service “VGAPPDB” has 2 instance(s).
Instance “VGAPPDB1”, status READY, has 1 handler(s) for this service…
Instance “VGAPPDB2”, status READY, has 2 handler(s) for this service…
Service “VGAPPDBXDB” has 2 instance(s).
Instance “VGAPPDB1”, status READY, has 1 handler(s) for this service…
Instance “VGAPPDB2”, status READY, has 1 handler(s) for this service…
Service “VGAPPDB_XPT” has 2 instance(s).
Instance “VGAPPDB1”, status READY, has 1 handler(s) for this service…
Instance “VGAPPDB2”, status READY, has 2 handler(s) for this service…
The command completed successfully

服务端测试登录：连续登录多次，皆正常

sqlplus VGOPDW/’***’@192.168.101.102:1521/VGAPPDB

客户端测试登录：连续登录多次，一部分登录正常，一部分会报如下下错：

sqlplus VGOPDW/’**’@192.168.101.102:1521/VGAPPDB
SQLPlus: Release 11.1.0.6.0 - Production on Tue Aug 4 14:49:04 2020
Copyright © 1982, 2007, Oracle. All rights reserved.
ERROR:
ORA-12545: Connect failed because target host or object does not exist

why ?