
Scenario 3 - Isolated domain, reporting capability, WSUS update
Overview
This topology is completely different from the others described in this article because another domain will be implemented on the perimeter network. This will allow use of the full set of capabilities that Forefront Client Security has to offer.
Figure 6 – Topology for Scenario 4.
The Forefront Client Security server that is going to be used on the perimeter network is using the one-server topology. Since the amount of computers located on the perimeter network is usually small, this topology should address all the needs.
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For more information on the one-server topology deployment, review the Forefront Client Security Deployment Guide at Microsoft TechNet.
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Although this scenario will allow the use of more features of the product, as the others, there are advantages and disadvantages to using it:
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Advantages
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Reporting features: this scenario will allow the administrator to use the reporting capabilities offered by Forefront Client Security. This helps the administration and maintenance of the computers located on the perimeter network.
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Centralize the deployment policies for computers on the perimeter network: the computers located on the perimeter network have different needs when compared to computers located on the internal network. With this topology, it will be possible to align those needs at the same time that it is possible to take advantages of the deployment policies by using Active Directory® group policy.
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Centralize the updates: as you can see on the diagram, the Distribution Server located on the perimeter network is getting updates from the internal Distribution Server. In the WSUS topology, this is called Mirror Update.
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Automatic installation: Forefront Client Security will be automatically installed on the computers located on the perimeter network.
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Disadvantages
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Add a new domain to the perimeter network: in this scenario, it is necessary to build a new domain that will be isolated from the internal network. This means to create another domain infrastructure with at least one Domain Controller dedicated to the computers located on the perimeter network.
Configuring the Web Server to get update from the WSUS on the perimeter network
In this scenario, the Web Server is joined to the CONTOSODMZ domain; therefore, the Windows Update policies will be distributed by the Domain Controller that is located on the perimeter network.
For the group policy, you can follow two approaches on the deployment:
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Create an organizational unit (OU) for the servers on the perimeter network, create a group policy object (GPO) for Windows Update, and link to this OU.
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Edit the Default Domain Policy directly.
To configure the group policy for that, follow the steps in Configuring Automatic Updates on TechNet. For the option specify intranet microsoft update service location, be sure to specify the name of the FCS Server on the perimeter network.
Since this server is a replica of the WSUS server that is located on the internal network, you don’t need to approve the updates for Forefront Client Security; they are already approved.
Configuring Forefront Client the Web Server
For this scenario, the Web Server will get the Forefront Client Security client automatically from the Forefront Distribution Server (WSUS). There are some points that you need to make sure are working correctly for this distribution to function as it should:
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Make sure that the Web Server is joined to the domain, and if you choose to deploy the GPO on the OU, then move the Web Server to the OU.
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Run GPUPDATE /FORCE on the Web Server in order to force the server to get the GPO.
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Run wuauclt.exe /detectnow on the Web Server in order to force the update.
Configuring ISA Server 2006
For ISA Server, the steps that were done in Scenario 2 will be the same ones used in this scenario.
Testing and Troubleshooting
For this scenario, we used the WSUS replica, which helps to manage the Internet Bandwidth and avoid that each WSUS server to retrieve updates from Microsoft Web site. During the first synchronization, you can observe if the traffic is correctly flowing through ISA Server 2006 by using the Monitoring option and launching the Logging view, as shown below:
Figure 7 – ISA Server 2006 Monitoring Logging.
As you can see on the screenshot above, there are three red squares on the main points of the screen.
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The first one is the filter that was used in order to allow a visualization of the traffic originating from the perimeter network.
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On the lower panel, we can see in the first square the name of the rule that is being used for this traffic
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In the last red square, we have the client agent that is being used to access the internal resource.
It is important to mention that this is the initial WSUS synchronization. After synchronization is finished, clients will begin downloading the updates from WSUS. You will notice that the Client agent will change and appear as Microsoft BITS, as shown below:
Figure 8 – BITS job passing through ISA Server 2006.
For troubleshooting purposes, you might need to use a protocol analyzer such as Network Monitor 3 in order to see further details on the traffic. The example below was taken on the internal interface of the ISA Server while the WSUS server on the perimeter network was doing the initial synchronization:
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Communication begins with the TCP three-way handshake:
ISACONTN2 FCSDIST TCPTCP: Flags=.S......, SrcPort=25830, DstPort=HTTP(80), Len=0, Seq=3596964623, Ack=0, Win=65535 (scale factor not found)
FCSDIST ISACONTN2 TCPTCP: Flags=.S..A..., SrcPort=HTTP(80), DstPort=25830, Len=0, Seq=1748899480, Ack=3596964624, Win=16384 (scale factor not found)
ISACONTN2 FCSDIST TCPTCP: Flags=....A..., SrcPort=25830, DstPort=HTTP(80), Len=0, Seq=3596964624, Ack=1748899481, Win=65535 (scale factor not found)
Notice that we are establishing the connection on port 80.
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Afterwards, the Windows Update agent will start the communication on port 80 and begin downloading updates from WSUS:
ISACONTN2 FCSDIST WinUpdV5WinUpdV5
ISACONTN2 FCSDIST HTTPHTTP: HTTP Payload
FCSDIST ISACONTN2 TCPTCP: Flags=....A..., SrcPort=HTTP(80), DstPort=25830, Len=0, Seq=1748899481, Ack=3596965248, Win=64911 (scale factor not found)
FCSDIST ISACONTN2 HTTPHTTP: Response, HTTP/1.1, Status Code = 200
FCSDIST ISACONTN2 HTTPHTTP: HTTP Payload
ISACONTN2 FCSDIST TCPTCP: Flags=....A..., SrcPort=25830, DstPort=HTTP(80), Len=0, Seq=3596965248, Ack=1748900342, Win=64674 (scale factor not found)
Notice here that the Network Monitor 3.2 parses the Windows Update traffic as WinUpdV5. This probably will change if you are not using Network Monitor 3.2 or higher.
For the server located on the perimeter network, you can review the file %systemroot%\WindowsUpdate.log in order to see the detection of the Forefront Client Security client:
Figure 9 – Forefront Client Security client detection process.
If you look at Figure 9, you will see three parts that emphasize the main portions of the detection:
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Part 1 – FCS client detection.
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Part 2 – Initializing the download.
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Part 3 – Downloading the client itself.
After we have the client detected and installed, we have to download the definitions:
Figure 10 – Download Manager starting the job and downloading the FCS client.
The next cycle of updates will download the Forefront Client Security hotfix shown in the example below:
Figure 11 - Downloading the new definitions.
After all the updates have been downloaded and installed, the shield will became green, and the Forefront Client Security console displays the versions for the antivirus and antispyware definitions.
Figure 12 – Forefront Client Security console after the update.