Fallback Printer Drivers in RDP and Terminal Server Sessions

Friday, August 29, 2008

Microsoft Remote Desktop Connection provides the ability for users to use the printers installed on their local computer within a Terminal Server session. This behavior is enabled by default, and can be changed in MSTSC (the Remote Desktop Connection client) in Options, Local Resources tab, Printers.

In order for this to work, a printer driver must be installed on the Terminal Server that matches the driver installed on the local computer. This is problematic, since you can't always be sure which printer is installed on connecting computers. If there is no matching printer driver on the server, the user will be unable to print to that printer within the RDP session. You will also see an error in the System Event Log similar to the following when the user
logs into the Terminal Server:

Event Type: Error
Event Source: TermServDevices
Event Category: None
Event ID: 1111
Date: 7/8/2008
Time: 12:51:15 PM
User: N/A
Computer: HOFS01
Driver HP LaserJet 4250 PCL 5e required for printer !!SERVER1! NetPrinter2 is unknown. Contact the administrator to install the driver before you log in again.

To handle this issue without having to install tons of drivers on your server, you can tell the server to use a "fallback printer driver." If the exact driver is not installed, the server will offer a fallback PCL or PS driver (or both) to use instead. This is configured in Group Policy as shown below. Note that this requires Windows Server 2003 SP1 or later.

For Windows Server 2003, open Group Policy and navigate to Computer Settings, Computer Configuration, Administrative Templates, Windows Components, Terminal Services, Client/Server data redirection, and configure the Configure Terminal Server Fallback Printer Driver Behavior option.

For Windows Server 2008, open Group Policy and navigate to Computer Configuration, Policies, Administrative Templates, Windows Components, Terminal Services, Terminal Server, Printer Redirection and configure the Specify Terminal Server Fallback Printer Driver Behavior option.

Configure the Terminal Server Fallback Printer Driver Behavior to Enabled, Show both PCL and PS if one is not found, as shown below.

When a client logs into the Terminal Server, you will now see the following event in the System Event Log and the client will be able to use their printer.

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Exchange Server Virtualization Support Policy Summary

Monday, August 25, 2008
Microsoft released their Microsoft Support Policies and Recommendations for Exchange Servers in Hardware Virtualization Environments document this month. I reviewed the support document and summarized the salient facts here.
Exchange 2007 Virtualization

Host Requirements:
  • A hypervisor virtualization solution that has been validated by the Windows Server Virtualization Validation Program
  • Adequate storage space to accommodate the host OS and components, paging file, management software and crash recovery (dump) files
  • Storage space must be allocated for Hyper-V temporary memory storage (BIN) files, equal to the amount of RAM allocated to each guest
Guest Requirements:
  • Exchange 2007 SP1 (or later) deployed on Windows Server 2008
  • Cannot have the Unified Messaging Role installed
  • The total maximum number of virtual processors cannot exceed the twice the number of physical cores.Typically 2 virtual processors are required for each Exchange server guest, but use this as a baseline
  • Large mailboxes (1GB and larger) require the use of Cluster Continuous Replication (CCR)
  • CCR nodes must be hosted on separate physical host servers to provide true redundancy and high availability
  • Mixing physical and virtual nodes is supported for CCR and SCC environments
  • Exchange supported backups must be run from the guest
  • Both legacy backups (using ESE streaming APIs) and Exchange-aware software-based VSS backups (Data Protection Manager) are supported
  • VSS backups of the an Exchange guest is supported if the guest uses only VHDs (not pass-through disks)
Guest Storage Requirements:
  • Supports fixed size VHDs, SCSI pass-through and iSCSI storage
  • Storage must be dedicated to one guest machine. In other words, a pass-through disk must be dedicated to one, and only one, guest.
  • Guest OS must use a minimum fixed-size VHD of 15GB plus the size of virtual RAM allocated to the guest
  • VHD limit is 2,040GB (nearly 2TB) in Hyper-V
  • Hub and Edge Transport servers require sufficient storage for message queues and log files
  • Mailbox servers require sufficient storage for databases and log files
  • iSCSI storage using an iSCSI initiator within the guest is supported. This offers greater portability, but decreased performance
Not Supported:
  • Dynamically expanding VHDs are not supported
  • Snapshots or differencing disks are not supported
  • Virtualization high availability solutions, such as Hyper-V Quick Migrations, are not supported. Only Exchange aware HA solutions (SCC, LCR, CCR and SCR) are supported.
  • VSS backups of the Exchange guest machine's pass-through disk from the host are not supported
  • Storage should be hosted on separate disk spindles from the guest's OS
  • Use SCSI pass-through storage to host transport and mailbox databases and transaction logs
  • When using iSCSI storage, configure the iSCSI Initiator on the host and present it as a pass-through disk to the guest
  • Use dedicated NICs with jumbo frames and not bound to a Virtual Network Switch, Gigabyte Ethernet, and isolated networks for iSCSI storage
Exchange 2003 Virtualization

Host Requirements:
  • The hardware virtualization software is Microsoft Virtual Server 2005 R2 or any later version of Microsoft Virtual Server
Guest Requirements:
  • Exchange Server 2003 SP2 (or later)
  • Microsoft Virtual Server 2005 R2 Virtual Machine Additions must be installed on the guest operating system
  • Exchange Server 2003 is configured as a stand-alone server and not as part of a Windows failover cluster
  • Each guest must have only one CPU
Guest Storage Requirements:
  • The SCSI driver installed on the guest operating system is the Microsoft Virtual Machine PCI SCSI Controller driver
  • The virtual hard disk Undo feature is not enabled for the Exchange virtual machine
  • Consider adding a dedicated virtual network adaptor for Exchange Server backups
  • Create separate fixed-size VHDs for Exchange Server databases and log files and store them on separate physical drives on the host
  • Exchange Server performance should be validated before production by using the Exchange Server 2003 Performance Tools
  • Make sure that the host server is sized correctly to handle the number of virtual machines that you plan to deploy
  • Use a storage solution that enables fast disk access
  • Antivirus programs should be configured to not scan VHD files
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Best. Birthday Present. Ever.

Saturday, August 23, 2008

My family decided to celebrate my birthday by pushing me out of a perfectly good airplane.

Bay Area Skydiving, in Byron, CA. I highly recommend this.

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How to Determine if a PST is ANSI or Unicode

Friday, August 22, 2008

PSTs created in Outlook 2002 and earlier versions are saved in ANSI format, which has a 2.1GB limit. Outlook 2003 and later offer both ANSI and Unicode formats for PST creation. Unicode PSTs have a theoretical 36TB limit which makes them a better choice, providing that backward compatibility is not an issue.

So how can you tell if a PST is in ANSI or Unicode format?

One way is to download a free utility called ListPSTs from http://www.maclean.com. You run this utility from the command line against the file or folder that contains the PST(s). The output displays the format of the PST files, as shown above.

Another way to tell without having to use a separate utility is by viewing the properties of the PST from within Outlook, itself. When you add the PST to Outlook, pay attention to the Format field of the PST, as shown below:

Unicode formatted PSTs will display the format, "Personal Folders File". ANSI formatted PSTs will display the format, "Personal Folders File (Outlook 97-2002)".

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Microsoft Exchange Virtualization and Licensing Announcements

Thursday, August 21, 2008
Microsoft announced some significant changes to its licensing and support policies for applications in hardware virtualization environments. There are two key parts of the announcement worth highlighting for Exchange customers:
  • Microsoft now supports Exchange Server 2007 SP1 running Hyper-V or hypervisors validated under the Microsoft Server Virtualization Validation Program (SVVP).
  • Microsoft is waiving its 90-day license reassignment policy to enable customers who virtualize Exchange to move their licenses between servers within a data farm as often as necessary.

Microsoft has published a new whitepaper, Microsoft Support Policies and Recommendations for Exchange Servers in Hardware Virtualization Environments, which includes Microsoft's support policy and recommendations for running Exchange Server 2003 in a Microsoft Virtual Server 2005 R2 environment. This article is a must-read for anyone considering a virtualized Exchange environment.

See this article on the Exchange Team blog for more details.

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How to Configure the SCL in Exchange

Tuesday, August 19, 2008

Recently I was asked what the proper Spam Confidence Level (SCL) should be for an Exchange 2007 installation. The answer is the ever-popular, "it depends."

The SCL is a value that Exchange assigns to each incoming SMTP email and is based on Microsoft's SmartScreen technology. This score determines how likely Exchange thinks an email message is spam. A rating of 0 means the message is not likely spam and a rating of 9 means the message is most likely spam.

SmartScreen is a "black hole" technology -- meaning that the algorithms and heuristics it uses for scoring is not published by Microsoft, thereby making it more difficult for spammers to create messages that can score lower and pass the filter. The Exchange server downloads new heuristics from Microsoft periodically.

Exchange 2003 SP2 introduced the Internet Message Filter (IMF) to score emails with an SCL rating. Exchange 2007 uses Content Filtering on the Anti-spam tab of the Edge Transport server to score emails (as shown below). It can also be enabled on a Hub Transport server if Edge Transport servers are not used. See How to Enable Anti-Spam Functionality on a Hub Transport Server.

Selecting the right SCL filter level is not an exact science. You're trying to filter obvious spam without accidentally filtering legitimate messages. You can use the following method to determine the starting point for your filter.

Using Perfmon to Select the SCL Filter Level
The best way to determine the appropriate SCL filter level is to use perfmon and examine the MSExchange Content Filter Agent object. Over time, the "Messages with SCL x" counters will increment and begin to show a trend.

In the example below, the Messages with SCL 0 through 7 counters are in the lower half of the scale. Messages with SCL 8 is off the charts at 270 -- more than all the lower SCL levels combined. From this data we can infer that it is safe to filter messages with an SCL higher than 7.

Note that these counters reset to zero upon restart of the server. It may take a little while before the trend appears.

Keep in mind that this is only the filter to begin with. You may have to adjust your filter up or down for your specific environment, but this will give you an excellent starting point.

SmartScreen filtering is just one of the anti-spam solutions available for Microsoft Exchange Server 2007. Other solutions include Sender ID Framework, Outlook Junk E-Mail Filter, and Microsoft Exchange Hosted Filtering. See the Microsoft AntiSpam Technologies website for more details.

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Managing Printers from the Command Line

Monday, August 18, 2008

I came across this handy way to manage printers from the command line. This makes it really easy to add, delete or change printers from logon scripts and batch files.

rem /y makes printer default

rundll32 printui.dll,PrintUIEntry /in /n file://server/printername
rundll32 printui.dll,PrintUIEntry /in /n
file://server/nextprintername /y

If you're wondering what else you can do with the printui.dll, just enter the following at the command line to bring up the command reference, as shown above:

rundll32 printui.dll,PrintUIEntry /?

Good stuff!

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