数据库服务器操作系统：
[ora12c@ora29 trace]$ uname -a
Linux ora29 2.6.39-400.17.1.el6uek.x86_64 #1 SMP Fri Feb 22 18:16:18 PST 2013 x86_64 x86_64 x86_64 GNU/Linux
[ora12c@ora29 trace]$
数据库版本：
[ora12c@ora29 trace]$ sqlplus -v
SQL*Plus: Release 12.2.0.1.0 Production
[ora12c@ora29 trace]$
今天，测试同事反应，他们.net应用程序连接的12c数据库出问题了，客户端应用程序报错：
登录数据库服务器，查看告警日志也发现一大堆的类似报错：
2017-06-14T13:16:40.873489+08:00
Errors in file /u03/app/diag/rdbms/ora12c/ora12c/trace/ora12c_ora_12761.trc (incident=26305):
ORA-03137: 来自客户机的格式错误的 TTC 包被拒绝: [kpoal8Check-3] [49152] [0] [0x000000000] [34856] [] [] []
2017-06-14T13:16:40.876466+08:00
Session (7,27633): Bad TTC Packet Detected: Inbound connection from client
Session (7,27633): Bad TTC Packet Detected: DB Logon User: BMITEST, Remote Machine: IIS APPPOOL\SE28, Program: w3wp.exe, OS User: WJW
Session (7,27633): Bad TTC Packet Detected: Client IP Address: 10.117.130.28
2017-06-14T13:22:23.986783+08:00
Errors in file /u03/app/diag/rdbms/ora12c/ora12c/trace/ora12c_ora_14136.trc (incident=26260):
ORA-03137: 来自客户机的格式错误的 TTC 包被拒绝: [kpoal8Check-3] [49152] [0] [0x000000000] [34856] [] [] []
2017-06-14T13:22:23.988291+08:00
Session (254,48328): Bad TTC Packet Detected: Inbound connection from client
Session (254,48328): Bad TTC Packet Detected: DB Logon User: BMITEST, Remote Machine: IIS APPPOOL\SE28, Program: w3wp.exe, OS User: WJW
Session (254,48328): Bad TTC Packet Detected: Client IP Address: 10.117.130.28
查看trc文件内容，没有有价值的东西：
[ora12c@ora29 trace]$ cat /u03/app/diag/rdbms/ora12c/ora12c/trace/ora12c_ora_14136.trc
Trace file /u03/app/diag/rdbms/ora12c/ora12c/trace/ora12c_ora_14136.trc
Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production
Build label: RDBMS_12.2.0.1.0_LINUX.X64_170125
ORACLE_HOME: /u03/app/oracle/product/12.2.0/db_1
System name: Linux
Node name: ora29
Release: 2.6.39-400.17.1.el6uek.x86_64
Version: #1 SMP Fri Feb 22 18:16:18 PST 2013
Machine: x86_64
Instance name: ora12c
Redo thread mounted by this instance: 1
Oracle process number: 82
Unix process pid: 14136, image: oracle@ora29
*** 2017-06-14T13:22:23.987987+08:00
*** SESSION ID:(254.48328) 2017-06-14T13:22:23.988026+08:00
*** CLIENT ID:() 2017-06-14T13:22:23.988035+08:00
*** SERVICE NAME:(ora12c) 2017-06-14T13:22:23.988044+08:00
*** MODULE NAME:(w3wp.exe) 2017-06-14T13:22:23.988053+08:00
*** ACTION NAME:() 2017-06-14T13:22:23.988061+08:00
*** CLIENT DRIVER:(ODPM.NET) 2017-06-14T13:22:23.988069+08:00
DDE: Problem Key 'ORA 3137 [kpoal8Check-3]' was flood controlled (0x6) (incident: 26260)
ORA-03137: 来自客户机的格式错误的 TTC 包被拒绝: [kpoal8Check-3] [49152] [0] [0x000000000] [34856] [] [] []
[ora12c@ora29 trace]$
查询oracle metalink网站，发现一个类似的报错文章：
