Microsoft uses the term Server Core to refer to a bare bones installation of Windows Server 2008, the next-generation version of Windows Server that's due out at the end of 2007. As the RTM date approaches,
Ward Ralston, Microsoft
Ward Ralston, a product manager on the Windows Server team explains how a Server Core installation simplifies server administration and addresses IT administrators' concerns about the command line interface usability. Ralston spoke with SearchWinIT.com recently about what he considers the advantages of Server Core and the misconceptions surrounding its security.
SearchWinIT.com: Why did you introduce Server Core?
Ward Ralston: We wanted to put Windows Server in its most highly reliable configuration. To do that we looked at the four core workloads we felt were the most important to customers, and those were DNS, DHCP, Active Directory and File Server. Then we ended up removing everything from the OS that wasn't necessary to support those four roles. So Windows Explorer, Media Player, even the graphical user interface, all DLLs and libraries that aren't needed to support just the OS, and those four core roles are completely removed. What you get with Server Core is this very small footprint install -- it's right around a gig.
Server Core is administered from a command line versus a GUI. Some believe managing from a command line will be onerous, such as having to learn the command prompts.
Ralston: Fear not, because one thing we've done with Server Core is enable a few ways for administrators to actually administer that remote box. One way is through the command line that's actually sitting there at the box. Of course, we have a new utility called OC setup [which is a command tool that installs Microsoft System Installer system files and passes packages to Package Manager for automatic installation] that allows users to configure roles on that box, so it makes that easy. We also put a little script in there that allows you to open up the Terminal Services port so you can come in and administer that box from another box using the command line.
At any other Windows Server 2008 box that you're sitting at, you can bring up the GUI administrative interface and connect to another Server Core box and administer it with the GUI as if that box was right there next to you. You don't really have to learn anything new if you're going to bust out a Server Core box for a particular role because the same familiar Microsoft Management Console tools from the other box can administer it.
You can also use Windows Management Instrumentation [WMI] to administer the Server Core box and fire off a PowerShell script on one box to administer the Server Core box as well. We also have a new technology that is pretty popular with our Unix administrators, something close to their secure shell called Windows Remote Shell so they can securely connect to a command prompt on another box and administer it as well.
But you can't use PowerShell in Server Core?
Ralston: You can use PowerShell to leverage WMI running on the Server Core install box. Also, in the future -- no date yet -- we are marching toward putting a componentized version of the .Net Framework in Server Core so that we can leverage both ASP.Net and PowerShell in future versions.
For IT administrators, what are the benefits of using Server Core?
Ralston: What they get out of it is reduced management. This is a nice durable minimal install that they can set up and not have to worry about. It's almost a set it up and forget it. At least that's how we hope it's going to go down with Server Core.
You started out with four Server Core roles and now you have nine roles. If you keep adding roles, do you think it lessens the perception of Server Core having a smaller attack surface?
Ralston: We don't see the Server Core install option as necessarily more secure than the regular Windows Server 2008 install option, and the reason for that is both the Server Core install option and full install of Server 2008 are fundamentally new and always shields up 100% of the time. The OC setup program in Server Core, which is actually the same setup program that is called in the full install version, is actually built on our Dynamic Systems Initiative.
For every potential role that can be on that box, we've mapped out all the dependencies, the constraints and put in what it means for that role to be healthy. So when you do run and install a role, only then do the bits actually get installed in the OS, and the features and functionalities in those ports get opened. To say that Server Core is more secure with four roles than with the full install version of 2008 with maybe two roles installed depends on how big the attack area of the box is.
What other roles can we expect in Server Core? What about Network Access Protection, for example?
Ralston: You need the Network Policy Server for Network Access Protection, which is not a feature or role that can be installed on Server Core. Server Core can be a NAP client. It can't be the NAP server, a policy server, but it can ensure its health is validated on the network.