US 20060167858 A1
A method and system for implementing policy by accumulating policies for a policy recipient from policy objects associated with a hierarchically organized structure of containers, such as directory containers (sites, domains and organizational units) that includes the policy recipient. Based on administrator input, policy settings for the policy recipient may be accumulated into a specific order by inheriting policy from higher containers, which may enforce their policy settings over those of lower containers. Policy that is not enforced may be blocked at a container. The result is an accumulated set of group policy objects that are ordered by relative strength to resolve any policy conflicts. Policy may be applied to a policy recipient by calling extensions, such as an extension that layers the policy settings into the registry or an extension that uses policy information from the objects according to the ordering thereof. Linking of group policy objects to one or more containers (e.g., sites, domains and organizational units) is provided, as is exception management. The effects of group policy may be filtered based on users' or computers' membership in security groups.
1. A computer-readable medium having computer-executable instructions for performing a method, comprising:
placing policy settings into a plurality of group policy objects, each policy object associated with at least one directory container;
accumulating the policy settings of the plurality of group policy objects into an accumulated policy for a policy recipient; and
associating the accumulated policy with the policy recipient.
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The present application is a continuation of copending U.S. patent application Ser. No. 10/254,155, filed Sep. 24, 2002, which is a continuation of U.S. patent application Ser. No. 09/268,455, filed Mar. 16, 1999, now U.S. Pat. No. 6,466,932, which is a continuation-in-part of U.S. patent application Ser. No. 09/134,805 entitled “System and Method for Implementing Group Policy,” filed on Aug. 14, 1998, now abandoned; all of the related applications are hereby incorporated by reference in their entireties.
The invention relates generally to computer systems and networks, and more particularly to an improved method and system for implementing policy for users and computers.
Lost productivity at employees' computer desktops is a major cost for corporations, often resulting from user errors such as modifying system configuration files in ways that render the computer unworkable. Productivity is also lost when a computer desktop is too complex, such as when the desktop has too many non-essential applications and features thereon. At the same time, much of the expense of administering distributed personal computer networks is spent at the desktop, performing tasks such as fixing the settings that the user has incorrectly or inadvertently modified.
As a result, enterprises such as corporations have established policies seeking to define settings for computer users. For example, a corporation may wish to have the same e-mail and word processing program on all their users' desktops, while certain users such as those in the engineering group have a common CAD program not available to users in the finance group. Another policy may selectively prevent a user from connecting to the Internet by writing information into the user's machine registry to prevent access. Centralized policy systems exist to allow an administrator some control over the settings that institute such policies, and provide benefits in scalability to assist in the administration of larger networks. For example, in networks organized into domains, (such as with Microsoft® Windows NT®4.0), such policies may be applied per domain, based on each domain user's membership in a security group.
However, there are a number of drawbacks present with existing policy systems. One such drawback is that the policies are essentially static, whereby a user can change the settings and simply avoid the policy. It is cost prohibitive to have an administrator or the like go from machine to machine to check the settings on a regular basis. It is possible to force mandatory profiles on a user at each log-on based on the user's group membership. However such mandatory profiles are too inflexible, in that essentially all settings made by an individual user are lost whenever the user logs off. For example, with mandatory profiles, customizations to a desktop, such as window placement, adding words to a user's spell checker and the like, which most enterprises would consider permissible and even desirable because they tend to increase an employee's efficiency, are lost when the user logs off.
Another significant drawback results from relying on a security group membership to determine the settings, particularly in that one group (the first group found for a user) determines that user's settings. Thus, if a user is a member of both the engineering and financial groups, the user will get only one set of policy settings. Present policy-determination systems, such as those basing policy on the domain plus membership in a security group, essentially follow a flat model, which does not fit well with a typical enterprise having a hierarchical organizational structure.
Briefly, the present invention provides a system and method for implementing policy for users and computers. Policy settings are placed into group policy objects, and each of the policy objects may be associated with one or more containers, such as hierarchically-organized directory objects (containers). e.g. a domain, site or organizational unit. Based upon administrator input, settings from policy objects are accumulated and associated with a policy recipient, whereby users' computers and the like receive the accumulated policy. To accumulate policy, the settings may be inherited from directory containers hierarchically above a policy recipient. The associated with other containers. The administrator's input also orders the group policy objects, whereby any conflicts are resolved by the ordering precedence, i.e., the policy's relative strength. Policy may be applied to a recipient by layering the policy settings, based on the ordering, weakest first such that strongest settings overwrite weaker settings, or by seeking policy information from the strongest to weakest policy until the desired policy is located.
A number of very flexible conditions based on an Active Directory hierarchy may be included. By default, an object's parent container in the hierarchy is the strongest factor, but other containers to the parent may affect an object's policy, and by default, group policy affects each of the computers and users in a selected active directory container. A default inheritance evaluates group policy starting with the active directory container that is furthest away whereby the Active Directory container closest to the computer or user has the ability to override policy set in a higher level container, in the order of Site, Domain, Organizational Unit or Units (SDOU). Moreover, there is provided an option to block inheritance of policy from higher parent containers, however there are also options that allow policy of a specific group policy object to be enforced so that group policy objects in lower level containers cannot override the policy settings of higher level containers, i.e., an enforced option takes precedence. In addition, the effects of group policy may be filtered based on users or computers membership in a security group.
Other advantages will become apparent from the following detailed description when taken in conjunction with the drawings, in which:
Exemplary Operating Environment
With reference to
A number of program modules may be stored on the hard disk, magnetic disk 29, optical disk 31, ROM 24 or RAM 25, including an operating system 35 (preferably Windows® 2000), one or more application program 36, other program modules 37 and program data 38. A user may enter commands and information into the personal computer 20 through input devices such as a keyboard 40 and pointing device 42. Other input devices (not shown) may include a microphone, joystick, game pad, satellite dish, scanner or the like. These and other input devices are often connected to the processing unit 21 through a serial port interface 46 that is coupled to the system bus, but may be connected by other interfaces, such as a parallel port, game port or universal serial bus (USB). A monitor 47 or other type of display device is also connected to the system bus 23 via an interface, such as a video adapter 48. In addition to the monitor 47, personal computers typically include other peripheral output devices (not shown), such as speakers and printers.
The personal computer 20 may operate in a networked environment using logical connections to one or more remote computers, such as a remote computer 49. The remote computer 49 may be another personal computer, a server, a router, a network PC, a peer device or other common network node, and typically includes many or all of the elements described above relative to the personal computer 20, although only a memory storage device 50 has been illustrated in
When used in a LAN networking environment, the personal computer 20 is connected to the local network 51 through a network interface or adapter 53. When used in a WAN networking environment, the personal computer 20 typically includes a modem 54 or other means for establishing communications over which may be internal or external, is connected to the system bus 23 via the serial port interface 46. In a networked environment, program modules depicted relative to the personal computer 20, or portions thereof, may be stored in the remote memory storage device. It will be appreciated that the network connections shown are exemplary and other means of establishing a communications link between the computers may be used. For purposes of the following description, a network administrator may be using the computer system 20 to establish and implement group policies in accordance with the present invention, while users subject to the group policies connect to the network via the remote computers 49.
In general, the present invention provides a method and system for implementing policies throughout a network in a highly flexible, scalable, extensible and efficient manner. To this end, any container capable of having attributes may have a group policy object attached thereto, and the group policy object may be evaluated to apply policy to policy recipients related to that container. For example, policy may be applied by specifying policy settings in the group policy objects, including registry-based settings, scripts, (computer startup and shutdown scripts, and user logon and logoff scripts), user documents and settings, application deployment, software installation, security settings and IP security. Indeed, policy objects may be extended to include virtually any desired information, as long as a client-side (or other) extension that uses the policy object is capable of interpreting and/or handling the information therein. Note that a server-side process may act as the client and interpret the policy, and pass the results to another client, e.g., a server-side extension may receive and process one or more policy objects and transmit the results of its processing to a router which then performs according to that policy.
In a preferred implementation described herein, the system and method utilize a highly flexible architecture of the Windows® 2000 operating system, in which an administrator can link policies to containers which are hierarchically organized directory objects representing sites, domains, organizational units and policy recipients (e.g., groups of users and computers) thereunder. Thus, although not necessary to the present invention, the group policy system and method preferably utilize a Windows® 2000 directory service, known as Active Directory 60 (of a domain controller 62,
Group policy settings may be created via a group policy editor 64 (a Microsoft Management Console snap-in or similar user interface), and these settings are ordinarily maintained in a group policy object (GPO) such as 66 1. Group policy objects 66 1-66n may store group policy information in locations including a group policy container and a group policy template. A group policy container is an Active Directory object that stores group policy object properties, and may include sub-containers for machine and user group policy information. Properties of a group policy container may include version information, which is used to ensure that the information is synchronized with the group policy template information, status information. e.g., whether the group policy object is enabled or disabled, and a list of components (e.g., extensions) that have settings in the group policy object. The group policy template is a folder structure preferably located in a system volume folder of the domain controller 62, and serves as the container primarily for file-based information, (e.g., scripts). The policy information may include one or more pointers to another location (e.g., a data file on a SOL server) where some or all of the actual policy information (or a further pointer thereto) is maintained. Policy information also may be stored in a virtual registry (e.g., a copy of some or all of a client machine's registry maintained in a file on the server, specifically in the group policy template), that may be used by an extension to put information into the client-machine's registry.
The group policy editor 64 or similar user interface tool (e.g., user interface 82) further allows an administrator to selectively associate the group policy objects with directory container objects 68 1-68p (
In accordance with aspects of the present invention, for each user of an organizational unit, the policy settings maintained in the policy objects 66 1-66n may be selectively accumulated in an order of precedence, inherited from the group policy objects associated with one or more higher-up organizational units 76 1-76j, the site 72 and/or the domain (e.g., 70 A), and/or blocked from being inherited. In general, in typical networks, the closer an organizational unit is to a user, the more likely that the administrator of that organizational unit will have a fair number of policies for that user. Mid-level policies are less likely to be present, and if present, are more likely to be suggested policy that may be blocked, as described below. Near the top of the hierarchy, very few policies are likely, but those that are present will be most likely important and thus enforced. Thus, to accumulate policy in a preferred implementation, policies are applied in a reverse hierarchical order, and higher non-enforced policies may be blocked, however higher policies that are enforced take precedence by hierarchical order.
To this end, as shown in
With respect to
The administrators can achieve the desired order by enforcing domain A's associated group Policy, ordering GPO3 above GPO4 within organizational unit D (76 D), and not selecting any blocking. The result, provided by an ordering mechanism 88 (
Beginning at step 700 of
Step 712 then tests if there is another group policy object at this level that has not yet been handled. As shown in
When there are no more group policy objects at the current level to place in the lists, step 712 branches to step 720 of
At step 702, the properties of the organizational unit OU1 are examined to determine if there is a group policy object associated therewith. Since in the present example of
As shown in
Step 720 of
Step 722 then determines that the non-enforced policy settings are blocked below Domain A, (via OU1, e.g., there is a blocking flag set), as shown in
As is understood from the above-described steps, the site's associated group policy object, GPO1 in the present example of
Thus, as expected from an analysis of
At this time the ordered list 90 of policy objects is complete, and the policies now may be applied to the user or users of OU2 and/or the machine on which the user is logging on. It should be noted that the machine policies are applied to the machine when the machine operating system is booted, while the user group policies are applied when a user of the group logs on. In addition, group policy may be processed periodically, (a default time of ninety minutes, factoring in a thirty-minute variable offset to distribute the network and server load, wherein both times may be changed by a policy), so that policy changes are updated on machines that are not frequently re-booted and for users that do not frequently log off.
Once the ordered list 90 of policy objects is complete, at least one client extension 100 is typically called (e.g., by a desktop management engine 102,
Another typical way in which policies are applied is to have at least some of the settings of the policy objects written to the registry of the user's machine. Applications and the like may then check the appropriate registry locations before taking certain requested actions, in order to perform or not perform the action according to the policy setting, (or some default value if no policy is defined for a particular setting). By way of example,
Still another way in which policy may be applied to a user is to maintain the ordered list 90 of group policy objects in association with a user/machine, and then walk through the list from strongest to weakest seeking a defined policy setting that satisfies a pending action request. For example, the various applications and settings therefor available to a group need not be written into the registry for each user, but rather maintained in the group policy objects. If the user wishes to run an application, the process attempting to run the application uses the list to first look to the strongest policy object to see if the action is allowed or denied, and if undefined, continues by querying the next strongest policy object in the list 90. The process will continue walking through the list 90 until an answer (e.g., allow or deny) is obtained, or until there are no more policy objects in the list to query, at which time a default answer may be used.
Additional features of group policy objects are also provided to facilitate administrator control over their operation. First, an association between a directory container and a group policy object may be disabled, e.g., via an administrator selection (
Another feature is that a group policy object includes both computer settings (HKEY_LOCAL_MACHINE) and user (HKEY_CURRENT_USER) settings, which may be separately disabled. Such disables are global, i.e., they apply to all links thereto, whereby all users under a directory container associated with the group policy object will not get the disabled portion or portions of the group policy object. For example, an administrator may disable the computer or user settings if either portion is not needed, providing a performance improvement. Similarly, an administrator may use this type of disabling to debug a group policy object problem, e.g., by turning off one portion of the group policy object at a time to determine which portion causes a problem.
The present invention also provides additional flexibility with respect to administering policy in a number of other ways. First, as described above, since group policy is maintained in objects, the containers may link to more than one group policy object and the group policy objects may be shared by multiple directory objects (containers), i.e., the same group policy object may be applied to multiple sites/domains/organizational units. For example, as shown in
Each policy object may also handle exception management in order to include or exclude certain users or groups of users from certain policy. To this end, each policy object may include an exclusion list of users and groups to which the policy will not apply and/or an inclusion list of users and groups to which the policy will apply. This is accomplished via the security descriptor associated with each object. An administrator may specify which groups of users and computers have “Apply Group Policy” access control entries in the security descriptor to determine access to the group policy object. In general, groups that have Apply Group Policy and read access to the group policy object receive the group policies therein, while groups that do not have Apply Group Policy or read access to the group policy object do not get the group policies therein. Note that security descriptors include one or more security identifiers and a bitmask of rights associated with each security identifier, and are capable of handling both inclusion and exclusion. For example, within a research group, certain users may be given a different Internet access policy than other users, e.g., via the security descriptor, apply the policy to listed users A, B and C, but no others in the group. Alternatively, via the security descriptor, the policy is applied to all users in the research group except X and Z who are specifically denied access to this policy object. This enables policy to be tailored to individual users without having to construct many separate groups to handle the various exceptions that typically arise in enterprises. Further, policy may be enforced for certain users and suggested for other users by splitting a groups policies into two groups, (e.g., Ae and A), and then using security access control to select which users in that group get which policy.
Another aspect of the present invention enables policy based on the machine's physical location, in addition to the user's logical function (reflected in the user's membership in various groups). In other words, policy may be made network topology aware. This is accomplished by associating a group policy object (e.g., 66 4) with a site 72, as shown in
The present invention also provides for an enterprise policy, a policy that is applied to all domains.
Moreover, in keeping with the invention, the desktop management engine 102 (
The desktop management engine 102 monitors for various types of events and notifies appropriate extensions of those events, whereby the extensions 100 may reapply the policy. A first type of event occurs when some change is made to the order of the group policy objects in the ordered list 90 with respect to each affected extension. For example, an administrator may remove (or add) a group policy object, whereby a new ordered list is generated for each extension. The new list is compared with the previous list for each extension to see if the list has changed for that extension, whereby the relevant extensions are separately called upon such a change, e.g., when policy is updated. To this end, the desktop management engine 102 saves the previous ordered list of group policy objects for each extension and compares it to the new list, taking into consideration which changes are relevant per extension.
By way of example, as shown in
To remove (or add) a group policy object from a list, the administrator may not actually remove (or add) the group policy object from a container, but may effectively remove (or add) the group policy object (e.g., GPOB) with respect to an extension. For example, the administrator may nullify all security settings from a group policy object, whereby that GPOB policy object is no longer relevant to the client-side security extension and is removed from the ordered list (GPOA, GPOC and GPOD) received by the security extension. However, GPOB may still be relevant to other extensions such as script and registry extensions, whereby those extensions receive (if necessary) the full ordered list, GPOA, GPOB, GPOC, and GPOD. Another reason that a GPO may be removed from (or added to) a list is that an administrator may change a user's security rights. For example, an administrator may change a user's security rights such that the user no longer has access to a group policy object. In such an event, the group policy object is removed from each of the ordered lists in which it is identified. Similarly, if security is changed to give a user access to a group policy object, that group policy object is accumulated in new appropriately-ordered lists for the user.
As represented in
Another change which extensions may register for notification of is changes to group membership. In general, whenever an administrator changes a user's membership in a group, e.g., by removing the member from a group or adding the member to a new group, the group policy desktop management engine 102 calls each extension registered for notification of this type of change. Because group memberships under directory containers determine which policy objects apply, each called extension will ordinarily reapply policy in response to the call, although the actual action taken by the extension is up to the extension.
Another factor that may be used to influence how group policy is applied is the rate at which data may be transferred. For example, if a link is slow, then certain policy information such as registry settings are applied, but other policy-related events such as software installations are not applied (because they would take too long), e.g., if scripts are not applied due to a slow link, the script extension may clear the scripts. More particularly, registry-based polices and security settings are applied by default (and cannot be turned off), while other policies are not applied by default. Other than the registry and security settings, another policy setting may specify whether the behavior should apply for slow links.
At each policy update, (which requires an IP connection) the data transfer rate is evaluated, as described below. Whenever a change from a slow to fast or fast to slow link is detected, a link transition flag indicating a change in the rate, along with a link rate flag (slow or fast), are used to call appropriately-registered extensions to provide the information needed to adjust for the link's data transfer rate. Of course, a finer distinction among rates may be provided other than simply fast or slow, e.g., relatively small software installations may take place for medium or fast connections, but not over slow connections, however a straightforward distinction between fast and slow is presently implemented.
To determine the connection rate, each client machine generally follows the steps set forth in
If at step 1406 a response was received and took longer than ten milliseconds, there may be a number of reasons why the response was slow, including that the connection is slow, or that the domain controller was temporarily busy. Thus, rather than assume the connection is slow, an actual data transfer rate is calculated, by looping up to three times, while discarding any clearly invalid values and averaging to balance any temporary anomalies. To this end, step 1406 branches to step 1408 where the domain controller is again pinged, this time with four kilobytes (4096 bytes) of data. At step 1410, the response time is recorded in a second variable, Time2, (provided the ping did not time out, whereby the process would effectively discard this invalid value and also Time1, e.g., by branching ahead to step 1416, not shown). If the response time took less than ten milliseconds as determined at step 1412, then as described above, the connection is considered to be fast, whereby step 1412 branches to step 1420 to adjust the link rate as necessary, after which the process is ended.
If the response again took more than ten milliseconds, step 1412 branches to step 1414 where the difference between Time1 and Time2, Delta, is calculated and, if the result is valid, is added to a Total. Another example of an invalid result is one in which the result is negative, i.e., the four-kilobyte transfer time (Time2) was smaller than the zero data transfer time, (Time1). Because Time1 corresponded to the time to transfer no data, under ordinary circumstances Time1 represents the time taken for overhead in the ping/response operation. In an ordinary case, the overhead time will be the same for the subsequent “4K” ping/response operation, and thus Delta equals the time to transfer four kilobytes of data after compensating for the overhead. However, as mentioned above, rather than calculate the data transfer rate from a single sample, an average is used, and thus step 1416 increments a loop counter and step 1418 evaluates whether the loop has been performed the desired number of times, (e.g., three). If not, step 1418 loops back to step 1402 where the transfer rate is again obtained. Note that while looping, if at any time a response can come back in less than ten milliseconds, the connection is considered to be fast and the process is ended.
Once the Total time for the three four-kilobyte transfers is obtained, this information may be used to determine whether the link is fast or slow. An administrator may set the slow versus fast threshold, or a default threshold may be used (e.g., 500 kilobits per second, i.e., 500 kbps). Because it is desirable to compare the actual data transfer rate with a threshold data transfer rate number that is meaningful to an administrator, steps 1430-1436 convert the Total time to a data transfer rate. To this end, step 1430 averages the time by dividing by the number of valid samples in the average, e.g., three, while step 1432 adjusts for the amount of data sent (four kilobytes) and the way in which time is measured (1000 ticks per second). Step 1434 converts bytes to bits, while step 1436 adjusts for the units of data transfer rates being in “kilobits” per second.
Once the measured data transfer rate (Z) is obtained, at step 1438 the actual rate Z is compared against a threshold value, established by default or set by an administrator. If below the rate, the link is considered slow (step 1440), while if above the rate, the link is considered fast (step 1442), whereby the link transition and link rate bits are adjusted accordingly.
Still another feature of the desktop management engine 102 enables group policy objects to be accumulated based on a machine's location in the hierarchy, instead of or in conjunction with the user's policy. By way of example, machines in a computer laboratory may need policy settings that carefully control what is allowed to be done to those machines, regardless of which user is logging on. A machine policy setting in the registry determines how policy is to be applied, in one of three modes, the normal mode, in conjunction with user policy, (merge mode), or instead of user-based policy settings (replace mode).
As can be seen from the foregoing detailed description, there is provided a method and system for implementing policy by accumulating policies for a policy recipient, (e.g., computers or users) from policy objects associated with containers. Policy settings for the policy recipient may be accumulated by inheritance, enforced by directory objects, blocked from being inherited, and layered in a specified order. Linking group policy objects is also provided, as is exception-based management.
While the invention is susceptible to various modifications and alternative constructions, certain illustrated embodiments thereof are shown in the drawings and have been described above in detail. It should be understood, however, that there is no intention to limit the invention to the specific form or forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention.