Disable BitLocker Active Directory Dependency

Let’s imagine that you have a Windows 7 system that was imaged.  Let’s imagine that the image is designed to easily connect to your infrastructure’s domain.  Let’s also imagine that you don’t want to add this particular system to your domain; you just want to use this system for a separate purpose, but save time by using your primary Windows 7 image.  Let’s also imagine that you want this system to have BitLocker enabled.  Your system meet’s all of Microsoft’s BitLocker requirements, but when you try to enable BitLocker, you get a nasty: BitLocker could not contact the domain.  Ensure that you are connected to the network or contact your system administrator error.

At this point, you have done a ton of research on how to turn off the Active Directory dependency for BitLocker, but have yet to find a solution.  Before you jump off the roof of your building, read below as I have your solution:

  1. Open gpedit.msc
  2. Navigate to: Computer Configuration > Administrative Templates > System > Trusted Platform Module Services.
  3. Disable the setting: Turn on TPM backup to Active Directory Domain Services.  This is probably the evil setting that is causing you all the problems.  But, just in case, continue on to the steps below anyway.
  4. Navigate to: Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption.
  5. Disable the setting: Store BitLocker recovery information in Active Directory Domain Services (Windows Server 2008 and Windows Vista).
  6. You may need to disable 1 more setting.  Navigate to: Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption > Operating System Drives.
  7. Disable the setting: Choose how BitLocker-protected operating system drives can be recovered.

Once all those Group Policy settings are disabled, your non-domain connected PC should have no (AD related) problems setting up BitLocker.

VirtualBox Bridged Networking Driver Problems

For most people this will not be an issue, however, there are a few individuals who are exhibiting network problems when using the VirtualBox Bridged Networking driver on the *host* machine.

The Problem:

The problem is that some systems running Windows 7 with the “VirtualBox Bridged Networking” driver installed will have network outage issues when resuming the system from hibernation.  The only way to fix this is the either reboot the machine, or disable/enable the NIC.

This bug has been reported here: http://www.virtualbox.org/ticket/4677, but it doesn’t seem like it will ever be fixed :(

The temporary solution:

Until Oracle gets around to fixing this bug, the following instructions below will correct the problem.  Do note, following the steps below will disable the bridged networking feature of VirtualBox.  However, utilizing this method gives you a simple avenue to re-enable it if you need to use it.

  1. Click the Start Menu / Start Orb.
  2. Type: “View network connections”
  3. Press Enter.
  4. A window should appear with a list of all the network devices attached to your system.
  5. Right click the adapter that is giving you a problem > Properties
  6. Uncheck “VirtualBox Bridged Networking Driver”
  7. Click OK, and you’re all set.

To enable the feature after it is disabled utilizing this method, follow the instructions above in reverse.

Alternatively, you can also just opt out of installing the VirtualBox Bridged Networking driver altogether.  However, doing so will not allow you to easily enable that great feature.

Solution for Viewing Blocked Media Content on Flash 10.1 Devices?

Recently, an increasing number of media companies have been blocking access to Flash 10.1 content on non-PC devices (i.e. Android Phones, Google TV, PS3, etc.).  The reasoning for this makes no sense as I can plug my laptop into my TV and watch sites like Hulu, Fox.com, and NBC.com content without any problems.  However, doing so on a game console, Google TV device, or even an Android Phone is somehow different in their view.  It shouldn’t be a DRM issue either, as that should be handled by the Flash player itself.

Oh well.  In the past, this could be worked around by simply altering the user-agent string on the browser.  In this case, the browser would basically lie to the server and trick it into thinking that it’s running on a PC web browser.  As a result, the content would play just fine.

However, that no longer works.  Instead of simply relying on the user agent string of the browser, they are now also looking at the version of Flash Player running on the device.  A string of the version of Flash you are running is sent to the server to check if you are using a “supported device.”  You can find out what your Flash version string is by visiting this page: http://kb2.adobe.com/cps/155/tn_15507.html.  Visiting that page should show you something similar to this:

Screenshot of the Flash Player version string

To verify that this string is actually being sent to the server, I opened up Wireshark and sniffed some traffic on Hulu.  While watching an episode of Hells Kitchen on Hulu, I sniffed for HTTP GET requests.  Below is a screenshot of the TCP Stream for the GET request:

TCP Stream of the GET Request

As you can see from the screenshot above, there are a lot of variables appended to the GET request.  The most interesting one is the: flashPlayer=WIN%2010%2C1%2C103%2C19. This tells the server which version of Flash Player the system is running. If you remove the delimiting characters from the GET request, you would see that the version string matches that of the string in the first screenshot above. If you were running Android, the version string would contain AND instead of WIN.

That is not the only GET request of interest.  Indeed, there are others which contain appended variables declaring the OS, and the browser being used.  All of this information together can identify the device accessing the service.  However, remember that because all of this code is coming from the client, it can be altered.

So, in theory, if we were to replace the Flash Player version (as well as any other string sent to the server that could reveal the identity of the device accessing the service) with known values that work (such as one from an ordinary PC), that device should be able to access the service, since the server thinks the device is just a regular, “supported” PC.

Unfortunately, modification of the packet on-the-fly is the problem.  I cannot find any suitable software that is capable of making these changes on-the-fly to the HTTP packets.  A proxy application would be best suitable for this purpose, as it can change the user-agent-string and potentially other variables within the packet before being sent out to the server.  Unfortunately, I cannot locate any software that would easily give me the granular control needed to make this work.

After looking into Squid, and Privoxy, the best application that I have tested so far is TcpCatcher (http://www.tcpcatcher.org/).  This is a great app that basically combines Wireshark with a proxy server for HTTP connections.  It can even perform find-and-replace functionality within the packet.  Unfortunately, as powerful as the application is, it does not have the ability to find-and-replace more than one variable at one time. For example, to make this work, I would need to change the user-agent string, as well as find-and-replace any instances of flashplayer=, flash=, and even os= with known values that work.  However, this application can only allow one or the other to be changed.  If I change the user-agent string, I cannot perform a find-and-replace on the packet.  Thus, it will not work to fix the problem, as we need to completely mask the identity of the accessing device and trick the server into thinking that it’s just an ordinary PC.

If anyone is able to locate software that can make this work, please post it in the comments.

Enable NIC Teaming/Bonding in Linux with Cisco Catalyst 6000/6500 Series Switches

Just about all new servers today have multiple NICs installed.  A great way to take advantage of those NICs is to team/bond them together.  NIC teaming/bonding is a great feature to add more availability/redundancy, and higher bandwidth to your server.

There are many different types of teaming that you can do.  This site lists all the available modes under Linux: http://www.linuxhorizon.ro/bonding.html **NOTE: NIC Bonding/Teaming on Windows is determined by the network driver.  Please consult your vendor’s documentation to enable the feature.**

Some of the NIC teaming modes will work without any additional switch configuration, however, other’s will not.  I will demonstrate how to perform NIC bonding on Ubuntu Linux 10.04 using mode 4: 802.3ad Dynamic Link Aggregation.  This mode will require switch configuration, as it will require the use of the LACP protocol.  I will demonstrate how to configure a Cisco Catalyst switch to support this feature, and setting it up is a lot easier than you think.  Despite these instructions being performed on Ubuntu, they should also work on other Linux distributions.  The switch configuration instructions are also applicable for Windows servers utilizing 802.3ad (LACP) NIC teaming.

Host Configuration (Linux):

The instructions that I used to set up NIC bonding in Ubuntu Linux 10.04.1 were very nicely outlined in this YouTube Video: (The video utilizes bonding mode 1: Round Robin. I would recommend mode 4: Link Aggregation)

For those who don’t have access to YouTube, follow the instructions below:

  1. Install ifenslave. On Ubuntu this can be performed by: sudo apt-get install ifenslave
  2. Create aliases for the bond.  To do that, a new file will need to be created at /etc/modprobe.d/aliases.  On Ubuntu, simply running the command: sudo nano /etc/modprobe.d/aliases will open a text editor and create the file.
  3. In the file, type the following and then save the file:
    alias bond0 bonding
    options bonding mode=4 miimon=100
  4. Modify the interfaces file to add the bond0 interface. To do that, first open /etc/network/interfaces. On Ubuntu, simply run the command: sudo nano /etc/network/interfaces.
  5. Comment out all existing network interfaces that are active.
  6. Add the following to the file:
    auto bond0
    iface bond0 inet static
        address <<insert ip here>>
        netmask <<insert netmask here>>
        gateway <<insert gateway here>>
        slaves eth0 eth1 # Place in the nic interfaces you are bonding
        # Place whatever other network info you need here.
  7. Save the file.
  8. Shutdown your server, and configure your switch. Once your switch is configured, turn your server on.

For troubleshooting issues, remember that your bond0 interface is seen by the OS as any type of ethernet interface. ifup and ifdown commands will work on that interface.

Host Configuration (Windows):

As mentioned above, this is dependent upon your drivers.  Please consult your driver documentation and software to enable this option.

Switch Configuration (Cisco Catalyst 6000/6500 Series [Running IOS]):

Log into your switch.  Once logged in, you must enter enable mode.  Next, follow the steps below:

  1. Configure your terminal: conf t
  2. Select the interface range you are using for the bonded/teamed interfaces: int range [starting interface] - [last interface number]
  3. Once you have the interface range you wish to modify, add in the following commands:
  4. shut
    switchport access vlan <<insert your vlan number here>> # All bonded interfaces must be on the same vlan
    channel-group <<insert the channel group number here (explained below)>> mode active # See below for more information
    # Place more interface configuration here (if needed)
    no shut  # Don't forget to turn on your interface
  5. Test the configuration, and then save it if you are happy with it.

In step three above, you need to make a channel group. A channel group tells the switch to treat the specified interfaces as one logical entity. You can have more than one, so pick the number corresponding to the host you are providing the nic teaming to. There are two modes that provide LACP functionality: active and passive. Cisco recommends that you enable active mode by default. I have found that this depends on the server. On the Windows servers that I have worked with, active mode worked just fine. However, on the Linux servers that I have tried this with, passive mode worked better.

That should be it. If I made any mistakes, or if you feel that more should be added, please feel free to leave a comment.

Fix Java apps not finding Java in 64-bit Windows

For Java apps to run in Windows, a JRE (Java Runtime Environment) must be installed.  If it’s installed, but your Java apps are throwing errors that it cannot find the JRE, then you will need to add an environment variable to point to the Java bin directory.

Here is a screenshot of such an error I received when trying to run the Android SDK:

AndroidSDK error showing that Java is not installed -- Even though it is.

(Also notice the typo in the above message: “Checking it it’s installed in …”)

Below are instructions for fixing this error on Windows 7 x64 with the 64-bit JRE installed:

  1. Click the “Start Orb”, and type: about system
  2. In the search results, you should see “System” appear.  Click on it, and you should have the “View basic information about your computer window” appear.
  3. In that window, on the left hand side, you should see a link to “Advanced system settings”.  Click it.  (Accept all UAC prompts)
  4. The “System Properties” window will appear.  Click the “Advanced” tab.
  5. On the “Advanced” tab, click the button towards the bottom of the window titled “Environment Variables…”
  6. The “Environment Variables” window should appear.  In this window, on the bottom half, you should see a section titled: “System variables”.  Scroll down that list for an entry titled: Path. Click the “Edit” button.
  7. The “Edit System Variable” window should appear.  In this window, select the textbox for “Variable value:”.  Scroll to the end of the entry, and add a semicolon (;) to the end of the line (assuming no semicolon is currently there).
  8. You will then need to locate where your Java bin directory is located.  For me, on 64-bit Windows 7 with the 64-bit JRE installed, it is located in the following path: C:\Program Files\Java\jre6\bin (This is the default location if installing the 64-bit JRE)
  9. Copy and paste the path to the bin directory after the semicolon we just added to the “Variable value:” textbox.
  10. Click OK to all the windows, and your application should work.

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