Oracle 10g OEM general error (Unknown host specified) solved

After installing oracle in the notebook, you can use the OEM console normally. However, after logging out, log on again or restart the system, or change the network environment of the notebook, problems may occur. The solutions to these problems have been used, but I have forgotten them for a long time. Today I have recorded these problems and solutions here.

1. Failed to start due to network environment changes
This problem occurs because the OEM cannot be started. Use the following command line:Copy codeThe Code is as follows: C:/Users/Administrator> set ORACLE_SID = TEST
C:/Users/Administrator> emctl stop dbconsol
Oracle Enterprise Manager 10g Database Control Release 10.2.0.1.0
Copyright (c) 1996,200 5 Oracle Corporation. All rights reserved.
Http: // IP: 1158/em/console/aboutApplication
.....

This problem has been encountered many times. It is often because the network environment (IP address) of your computer changes, so that oracle will construct an OEM address based on your current IP Address at startup, instead of the IP address you installed. Note the above: http: // IP: 1158/em.
To solve this problem, I also rebuilt the OEM based on the methods found by google, but this method is still cumbersome and long, and often encounters inexplicable errors.
The simplest solution is to modify $ ORACLE_HOME/BIN/emctl. bat file, open this file, and add the following two lines of code at the beginning of the file or in a proper location (for example, after 42 rows of setlocal:Copy codeThe Code is as follows: set ORACLE_SID = TEST
Set ORACLE_HOSTNAME = Laidye

Note that ORACLE_HOSTNAME should be set to the name you read and set during the initial installation of oracle. It is often the name of your computer when installing oem in a network environment, for more information, see the $ ORACLE_HOME/HOSTNAME_SID folder. In this way, the OEM can be started normally no matter how the network environment you are using changes.

2. An error is displayed on the logon page.
2.1 error java. lang. Exception: Exception in sending Request: null
The root cause of this problem is the time zone setting problem. The solution is to modify the time zone of the configuration file.
Stop the OEM, open $ ORACLE_HOME/HOSTNAME_SID/sysman/config/emd. properties, and set the last line
AgentTZRegion = GMT
Change
AgentTZRegion = Asia/Shanghai
For specific time zone names, you can view $ ORACLE_HOME/sysman/admin/supportedtzs. lst or Select TZNAME From v $ timezone_names through data query;
In general, you can restart the instance after the configuration is complete. This error may also occur: Database Error Io exception: Unknown host specified

2.2 Database Error Io exception: Unknown host specified
If you encounter this problem, manually register the time zone parameter configured in the configuration, and use the following command:Copy codeThe Code is as follows: set ORACLE_SID = youdbsid
Emctl stop dbconsole
Emctl config agent getTZ
Emctl start dbconsol
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