Controlling Exchange ActiveSync device access using the Allow/Block/Quarantine list
Published Nov 15 2010 04:38 PM 287K Views

What is the Allow/Block/Quarantine list?

In Exchange 2010 we added a feature called the Allow/Block/Quarantine list (or ABQ for short). This feature was designed to help IT organizations control which of the growing number of Exchange ActiveSync-enabled devices are allowed to connect to their Exchange Servers. With this feature, organizations can choose which devices (or families of devices) can connect using Exchange ActiveSync (and conversely, which are blocked or quarantined). Some of you may remember my previous post on this topic dealing with organizations that do not have Exchange 2010 and thus I wanted to show you the far better way you can do this in Exchange 2010 (which is also what you will see in Office 365 and Exchange Online if you are looking at our cloud-based offerings). It is important to understand that the ABQ list is not meant to displace policy controls implemented using Exchange ActiveSync policies. Policy controls allow you to control and manage device features (such as remote wipe, PIN passwords, encryption, camera blocking, etc.) whereas the ABQ list is about controlling which devices are allowed to connect (for example, there may be a lot of devices that support EAS PIN policies, but some IT departments only want to allow certain devices to connect to limit support or testing costs). The easy takeaway is that Exchange ActiveSync policies allow you to limit device access by capabilities while the Allow/Block/Quarantine list allows you to control device access by device type. If you're curious as to what devices OS support which policies, the Wikipedia article we blogged about is a good place to look.

Different device access models for different folks

When we designed the ABQ list, we talked to a lot of organizations to find out how all of you use (or wanted to use) this kind of technology. What we realized is that there is a continuum of organizations; from permissive organizations that let employees connect whatever device they have to their Exchange Server, all the way to restrictive organizations that only support specific devices. Since we always want to make our software as flexible for IT as possible (as we know there are a lot of you folks that are using our software in a lot of different ways) we created this feature so that no matter which type of organization you are (or even if you are one that is in between these two extremes) we could help meet your needs. Below are some descriptions and "how-to"s for using the ABQ list in these different ways.

The restrictive organization

Restrictive organizations follow a more traditional design where only a set of supported devices is allowed to connect to the Exchange server. In this case, the IT department will only choose to allow the particular devices they support and all other devices are blocked.

It's important to note that a restrictive organization is created by specifying a set of allowed devices and blocking the unknown.

The permissive organization:

Permissive organizations allow all (or most) to connect to their Exchange Server. In these cases, the ABQ list can help organizations block a particular device or set of devices from connecting. This is useful if there's a security vulnerability or if the device is putting a particularly heavy load on the Exchange server. In these cases, the IT department can identify the misbehaving device and block that device until a fix or update for that device brings it into compliance. All other devices, including the unknown devices, are given access.

The one off case:

Of course, if you are limiting the devices that connect to your organization, there's almost always a need for an exception. Whether it's testing a new device before rolling it out to the organization as a supported device, or an exception made for an executive, we wanted to give you the ability to make an exception without allowing all users with that device to access your organization's email and PIM data.

When to quarantine:

Quarantining devices is useful when an IT department wants to monitor new devices connecting to their organization. Both permissive and restrictive organizations may choose to employ this mechanism. In a permissive organization, quarantine can be used so that IT administrators know what devices, and which users, are making new connections. In restrictive organizations, this can be used to see who is trying to work around policy and also gauge demand from "Bring Your Own Device" (BYOD) users. Now that we've gone through the theory, let's talk about how we would do this in practice.

Accessing the ABQ settings:

  1. Log in to the Exchange Control Panel (ECP) (you can also access the ECP from Outlook Web App (OWA) by selecting Options > See all options)
  2. In the ECP, make sure you are managing My Organization (#1 in the screenshot below). Be aware that most users won't see the "My Organization" option — it's only visible to users with Exchange Administrator access.
  3. Select Phone & Voice (#2 in the screenshot below) > ActiveSync Access tab (#3 in the screenshot below). This is the Allow/Block/Quarantine configuration screen.
Note for all you Exchange Management Shell (EMS) gurus, you can also configure device access using PowerShell cmdlets if you prefer.

Creating a device (or a family of devices) rule:

To create a new rule, select New from the Device Access Rules section of the ABQ page (#5 in the screenshot above). When setting up a rule for a device, it is important to understand the difference between the "family" of the device and the specific device. This information is communicated as part of the EAS protocol and is reported by the device itself. In general, you can think of the deivce rule as applying only to the particular device type (like an HTC-ST7377 as shown in the image below) whereas a device family might be something more broad like "Pocket PC". This distinction between the specific (device type) and the general (device family) is important since many device manufacturers actually release the same device with different names on different carriers. To make it so that you don't have to make a separate rule for each device. For instance, the HTC Touch Pro was available on all four majour US carriers as well as some of the regional ones, and that's just the USA, not to mention the other versions around the world. As you can see, making a rule for each of those different devices (which are all in the same family and effectively the same device) could mean a lot of extra work for IT, so we added the family grouping to help you make good decisions about devices in bulk. It's important to note that when making a new rule you select the device family or the model but not both. Once you've selected the device or a device family, you can then choose what Exchange will do with that device (in this example, I'm just going to do a specific device). This brings you to the New Device Access Rule page. The easiest way to set the rule is to select Browse, which will show you a list of all the devices or device families that have recently connected to your Exchange Server. Once you've selected the device or family, you can choose the action to take. This is where you can choose to block the device if you are a permissive organization looking to limit a specific device for a specific reason or where you can set access rules if you are a restrictive organization (in such a case you would just create an allow rule for each supported device and then set the state for all unknown devices to block (we'll talk about how to set the action for unknown devices in the next section)). Once you select the action (Allow access, Block access, or Quarantine), click Save and you're done! You can repeat this process for each rule you want to create. You can also have both block and allow rules simultaneously.

Setting up a rule for unknown devices:

To access the rule for unknown devices, select Edit (#4 in Figure 5 above). On the Exchange ActiveSync Settings page, you can configure the action to take when Exchange sees a user trying to connect with a device that it does not recognize. By default, Exchange allows connections from all devices for users that are enabled for EAS. This example configures the Exchange organization to quarantine all unknown devices. This means that if there's no rule for the device (or device family) or if there's no exception for the particular user, then an unknown device will follow this behavior. Quarantine notifications We have the ability to specify who gets an email alert when a device is placed in quarantine. You can add one or more administrators (or users) or even a distribution group to this list of notified individuals. Anyone on this list will receive an email like the one shown in the screenshot below. The notification provides you information about who tried to connect the device, the device details and when the attempt was made. Custom quarantine message You can also set a custom message that will be delivered to the user in their Inbox and on their device. Although the device is in quarantine, we send this one message to the device so the user doesn't automatically call help desk because their device isn't syncing. The custom message is added to the notification email to the user that their device is in quarantine. The user and device will also now appear on the Quarantined Devices list on the ABQ configuration page.

Managing Quarantined Devices

The device will stay in quarantine until an administrator decides to allow or block the device in quarantine. This can be done by selecting the device and then clicking on the Allow or Block buttons in Quarantined Devices. This creates a personal exemption (the "one off case" mentioned earlier). If you wish to create an access rule that is to apply to all devices of the same family or model, you can select Create a rule for similar devices to open a new, prepopulated, rule.

Making changes:

Of course we realize that many organizations are dynamic and have changing requirements and policies. Any of the rules that have been set up can be changed dynamically by accessing the ABQ page in the ECP and editing, deleting, or adding the desired rule. Adam Glick (@MobileGlick) Sr. Technical Product Manager

P.S. To read about Microsoft's licensing of Exchange ActiveSync, check out this article on Microsoft NewsCenter. Julia White also put up a more business focused blog in the UC Blog about the importance of EAS to Exchange 2010 customers.

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