限制IP访问Oracle

    与防火墙类似的功能，Oracle 提供限制与允许特定的IP或主机名通过Oracle Net来访问数据库。这个功能由sqlnet.ora配置文件来实
现。该文件通常$ORACLE_HOME/network/admin/ 目录下，与tnsnames.ora以及listener.ora位于同一路径。用法也比较简单。通过监听器的
限制，实现轻量级访问限制，比在数据库内部通过触发器进行限制效率要高。
1. 实现方式
    通过在sqlnet.ora文件中增加下列记录来实现 

[sql] view plaincopyprint?
01.tcp.validnode_checking = yes
02.tcp.invited_nodes = (hostname1, hostname2，ip1,ip2)
03.tcp.excluded_nodes = (10.103.11.17,hostname1,hostname2)

    当使用invited_nodes时，则所有没有包含在invited_nodes值中的IP或主机将无法通过Oracel Net连接到数据库。而如果使用
    excluded_nodes时，除了excluded_nodes值中列出的IP和主机不可访问之外，其余的节点都可以访问数据库。通常情况下，更倾向于使
    用excluded_nodes参数。
2. 注意事项
    使用excluded_nodes与invited_nodes的一些特性
        不支持通配符的使用(如hostname不能写为svhs0*，IP地址不能写为10.103.11.*）
        excluded_nodes与invited_nodes为互斥方式，要么使用前者，要么使用后者
        如果tcp.invited_nodes与tcp.excluded_nodes都存在，则tcp.invited_nodes优先
        要将本地地址，或者Cluster群集其他节点的地址都加入到允许列表，否则监听器可能无法启动
        修改之后，一定要重起监听或reload才能生效，而不需要重新启动数据库
        仅提供对TCP/IP协议的支持
3. 实战演习

[sql] view plaincopyprint?
01.-->使用tnsping demo92，连接正常
02.    C:\>tnsping demo92
03.
04.    TNS Ping Utility for 32-bit Windows: Version 11.2.0.1.0 - Production on 25-JUN-2011 18:55:39
05.    Copyright (c) 1997, 2010, Oracle.  All rights reserved.
06.    Used parameter files:
07.    d:\app\Robinson\Oracle_client\product\11.2.0\client_1\network\admin\sqlnet.ora
08.
09.    Used TNSNAMES adapter to resolve the alias
10.    Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 10.103.11.20
11.    9)(PORT = 1521))) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = demo92)))
12.    OK (0 msec)
13.
14.-->查看配置文件
15.    [oracle@test admin]$ more sqlnet.ora
16.    # SQLNET.ORA Network Configuration File: /oracle/92/network/admin/sqlnet.ora
17.    # Generated by Oracle configuration tools.
18.
19.    NAMES.DIRECTORY_PATH= (ONAMES, TNSNAMES, HOSTNAME)
20.
21.    #Added by Robinson
22.    tcp.validnode_checking = yes
23.    tcp.excluded_nodes = (10.103.11.17)
24.
25.-->重新reload
26.    [oracle@test admin]$ lsnrctl reload listener_demo92
27.
28.    LSNRCTL for Linux: Version 9.2.0.8.0 - Production on 26-JUN-2011 10:03:11
29.
30.    Copyright (c) 1991, 2006, Oracle Corporation.  All rights reserved.
31.
32.    Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=test)(PORT=1521)))
33.    The command completed successfully
34.
35.-->再次tnsping时，收到TNS-12547错误
36.    C:\>tnsping demo92
37.
38.    TNS Ping Utility for 32-bit Windows: Version 11.2.0.1.0 - Production on 25-JUN-2011 19:01:21
39.    Copyright (c) 1997, 2010, Oracle.  All rights reserved.
40.    Used parameter files:
41.    d:\app\Robinson\Oracle_client\product\11.2.0\client_1\network\admin\sqlnet.ora
42.
43.    Used TNSNAMES adapter to resolve the alias
44.    Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 10.103.11.20
45.    9)(PORT = 1521))) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = demo92)))
46.    TNS-12547: TNS:lost contact
47.
48.-->下面的演示中如果excluded_nodes与invited_nodes都存在，则invited_nodes优先，不再演示
49.    [oracle@test admin]$ more sqlnet.ora
50.    # SQLNET.ORA Network Configuration File: /oracle/92/network/admin/sqlnet.ora
51.    # Generated by Oracle configuration tools.
52.
53.    NAMES.DIRECTORY_PATH= (ONAMES, TNSNAMES, HOSTNAME)
54.
55.    #Added by Robinson
56.    tcp.validnode_checking = yes
57.    tcp.excluded_nodes = (10.103.11.17)
58.    tcp.invited_nodes = (10.103.11.17)

4.使用触发器限制单用户或IP段 

[sql] view plaincopyprint?
01.-->限制单用户从单IP登录，下面限制scott用户从客户端的登录
02.    CREATE OR REPLACE TRIGGER disablelogin
03.        AFTER logon ON scott.schema    -->注意使用方式为username.schema
04.    DECLARE
05.        ipaddr VARCHAR2(30);
06.    BEGIN
07.        SELECT sys_context('userenv', 'ip_address')
08.        INTO   ipaddr
09.        FROM   dual;
10.        IF ipaddr = '10.103.11.17' THEN
11.            raise_application_error('-20001',
12.                        'You can not login,Please contact administrator');
13.        END IF;
14.    END disablelogin;
15.    /
16.
17.-->限制IP段登录
18.    CREATE OR REPLACE TRIGGER chk_ip_range
19.        AFTER logon ON scott.schema
20.    DECLARE
21.        ipaddr VARCHAR2(30);
22.    BEGIN
23.        SELECT sys_context('userenv', 'ip_address')
24.        INTO   ipaddr
25.        FROM   dual;
26.        IF ipaddr LIKE ('10.103.11.%') THEN
27.            raise_application_error('-20001',
28.                        'You can not login,Please contact administrator');
29.        END IF;
30.    END chk_ip_range;
31.    /