The reason and method of Oracle user being locked __oracle

Reasons and methods for Oracle users being locked  
when logging in, they were told that test user was locked in
1, logged in with DBA role, unlocked, set specific time format to view specific time
Sql> alter session Set nls_date_format= ' Yyyy-mm-dd hh24:mi:ss '; The
session altered.　　
2, view specific locked time
sql> Select Username,lock_date from dba_users where username= ' TEST ';
USERNAME lock_date
-------------------------------------------------
TEST 2009-03-10 08:51:03
3, Unlock
SQ l> alter user test account unlock;
User altered.
4, view is that IP caused by the test user is locked

View $oracle_home/network/admin/log/listener.log Log
10-mar-2009 08:51:03 * (Connect_data= (SID=lhoms) (SERVER= Dedicated) (Cid= (program=oracle) (HOST=OMSTESTDB) (user=oraoms)) * (Address= (PROTOCOL=TCP) (host=10.69.1.11) (PORT= 49434)) * Establish * lhoms * 0
10-mar-2009 08:51:03 * (Connect_data= (sid=lhoms) (server=dedicated) (CID= (PROGRAM=orac Le) (HOST=OMSTESTDB) (user=oraoms)) * (Address= (PROTOCOL=TCP) (host=10.69.1.11) (port=49435)) * Establish * lhoms * The 0www.examda.com exam will go to the exam.
This can be known as the above 10.69.1.11 IP attempt multiple failed login caused by the lock
Note:
General database default is 10 attempts failed to lock users
1, view Failed_login_　　The value of attempts
Select * from Dba_profiles
2, modified to 30 times
Alter profile default limit failed_login_attempts
3. Modify to unlimited time (for security reasons, not recommended)
Alter profile default limit Failed_login_attempts unlimited;