Oracle Enterprise Manager Console – Password Expired

Today I got the following message while trying to access the oracle enterprise console.
Failed to connect to database instance: ORA-28001: the password has expired (DBD ERROR: OCISessionBegin).
The log was draining the following errors.

[ApplicationServerThread-5] ERROR eml.OMSHandshake processFailure.806 - OMSHandshake failed.
java.sql.SQLException: ORA-28001: the password has expired
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:331)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:283)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:278)
at oracle.jdbc.driver.T4CTTIoauthenticate.receiveOauth(T4CTTIoauthenticate.java:792)
at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:365)
at oracle.jdbc.driver.PhysicalConnection.(PhysicalConnection.java:519)

To fix the issue
================
* Stop enterprise manager -> emctl stop dbconsole
* login to sqlplus as sysdba -> sqlplus "/as sysdba"
* reset sysman password -> alter user sysman identified by <the new password> ;
* reset dbsnmp password -> alter user dbsnmp identified by <the new password> ;
* find the emoms.properties file -> find <ORACLE_HOME> -name emoms.properties
* select the emoms.properties file in ORACLE_HOME/HOST_SID/sysman/config
* Change sysman password in emos.properties -> oracle.sysman.eml.mntr.emdRepPwd=New Password
* Change encrypted to false in emos.properties -> oracle.sysman.eml.mntr.emdRepPwdEncrypted=FALSE
* Find the targets.xml file in ORACLE_HOME/HOST_SID/sysman/emd
* Change dbsnmp password in targets.xml and set encrypted to FALSE -> <Property NAME=”password” VALUE=”<New Password>” ENCRYPTED=”FALSE”/>
* Restart the enterprise console -> emsctl start dbconsole

Oracle 11g sets password expiry by default. This is the reason behind getting the password expiry messages.
To stop this happening in the future do the following.
* Login to sqlplus as sysdba -> sqlplus "/as sysdba"
* Execute ->ALTER PROFILE DEFAULT LIMIT FAILED_LOGIN_ATTEMPTS UNLIMITED PASSWORD_LIFE_TIME UNLIMITED;

Steps to reconfigure the DB Control in case of a host name change etc.
===============================================
set oracle_sid=YourInstanceName
emctl stop dbconsole
emca -deconfig dbcontrol db
emca -repos recreate
emca -config dbcontrol db
emca -reconfig ports -DBCONTROL_HTTP_PORT 80 (This port change is optional)

References - http://www.eggwater.co.uk/wordpress/?p=4