Windows Server 2008 in the spotlight

Microsoft's new server OS reviewed

In our testing of Windows Server 2008 gold code, shortly before its official release last week, we found that Microsoft has made a number of improvements to its flagship server OS.

For example, new server administrative role schemes boost security, the Server Manager program improves manageability, Internet Information Server (IIS) web management functionality is revamped, Active Directory is easier to control, and Windows Terminal Services has been redesigned. Windows Server 2008 is also significantly faster than Windows Server 2003, especially when client machines are running Vista.

Unfortunately, a highly anticipated feature of Windows Server 2008, the Hyper-V server virtualisation tool, is missing. Microsoft includes a beta version of Hyper-V with Windows Server 2008 editions, but it will not release final code until the third quarter of this year.

Also missing is compatibility between non-Windows (and older Windows) clients and Microsoft's Network Access Protection (NAP) scheme, Microsoft's version of NAC.

We tested the NAP scheme as implemented in Windows Server 2008 and found that it works as long as the client is running Windows XP or Vista. But it won't let clients running any other brand of operating system have access to its protected resources, thus hampering the potential success of the NAP scheme, because all client types must be vetted for NAC to work effectively.

Microsoft wants administrators of Windows Server 2008 to think of the server as playing certain roles. Server roles are aggregated objects that suit commonly thought-of services, such as print services, file sharing and IIS-based web services.

The services running on any role-based server are partitioned and enabled through Server Manager, Microsoft's renamed, revamped administrative application — either through its GUI or CLI front end. It's a vast improvement over the 'Configure Your Server' routines found in Windows 2000 and 2003 editions. Once successfully enabled, the roles can be easily changed. The CLI version allows scripted initial or remote role changes for administrators. Server Manager adds an important improvement over prior management applications: it checks application dependencies thoroughly before it effects installation, changes, deletions or other alterations.

We got a nearly immediate taste of higher security these server roles allow when we installed Windows 2008 Server — strong administrative passwords are now required as the default.

Active Directory Certificate Services have been redesigned, and now join with Group Policy settings to allow easier certificate enrollment, discovery and storage. The public-key infrastructure that was difficult to establish, monitor and maintain in Windows 2003 Server editions has improved dramatically as choices for certificate management (including storage, issuance and certificate vetting) are wider than ever before.

A side benefit is that IPSec encryption can be used with a number of previously unavailable cryptography methods, such as elliptic-curve Diffie-Hellman, allowing a simple but previously difficult security hole to be patched. Windows 2008 can provide comprehensive network encryption services, network-wide.

In addition to Server Manager, server-based Windows Firewall MMC snap-in helped us configure and manage host-based security more easily. Windows Firewall on Windows 2008 Server-based networks can be now controlled by system enforced Group Policy Objects (GPO) within Active Directory. The ability to enforce Windows Firewall settings within an Active Directory domain provides a hierarchically enforced mechanism that thwarts branch office or subsidiary server settings made by local administrators.

The GPOs can now define server IP address admittance, allowing servers to simply ignore traffic from all but specific addresses. Policies for specific routes are inherited by all clients and servers admitted to the Active Directory-controlled network, which then allows possible intruder activity to be more readily discerned from the noise of general traffic.

However, this admittance control alone doesn't reduce the effects of TCP SYN DOS attacks, but other TCP/IP settings shipping with only Windows Server 2008 can be used to reduce the effect of TCP connection-focused distributed denial-of-service (DoS) attacks.

We tested network I/O performance using both emulated I/O and various traffic/assault tests and found Windows 2008 Server performance has improved — especially when Vista is the client.

Microsoft's new client and server TCP/IP stacks, encompassing both tcpip.sys and the older Winsock API kit, have been updated. The TCP/IP stack contains native, rather than emulated IPv6 support. Choosing either IPv4 or IPv6 support is an interchangeable action, and management is identical.

The new stacks also have the ability to dynamically respond to communications latency in network connections, as they possess the ability to dynamically change TCP packet window size.

SMB 2.0, unlike SMB 1, has performance enhancements that are designed to allow greater speed. One of these enhancements allows for larger buffer sizes when both reading and writing files. More open files can also be sustained at a single exercise like a file folder copy, or the number of files open-for-write concurrently.

In our testing we found that under light loads, the effects in terms of speed of tasks like copying folders, streaming media and loading complex web pages aren't strongly demonstrated, but the effects under heavy loads favours performance for Vista.

This means that there's a two-class affinity for clients of Windows 2008 Server Editions — Vista and everyone else. If you have a client with the new stack, you're more efficient, and, therefore faster under higher loads, but you're a second-class citizen if your stack isn't up to date.

Vista supports and is shipped with both SMB 1.0 and SMB 2.0, whereas XP supports only SMB 1.0. Microsoft claims that Vista should be able to obtain better file/folder copy speeds over XP, especially in networks with higher latency. In our lab, higher latency (emulation over Ethernet 10Base-T) or low latency (same network subsegment with Gigabit Ethernet), Vista completed folder copies at least 35% faster than Windows XP SP2. As SMB emulation for Apple's MacOS and most Linux clients are based on Samba, which is also based on SMBv1, these clients were tested and, as expected, showed no improvement in speed when connected to Windows 2008 Enterprise Edition over Windows 2003 Enterprise edition on the same hardware.

Windows Server 2008 also supports TCP/IP processing to be offloaded to supported network cards. In such a relationship, the TCP/IP Offloading Engine (TOE) card doesn't interrupt any of the CPUs to service TCP/IP traffic and protocol relationship requests, ostensibly speeding up network throughput.

When we swapped from a Broadcom Gigabit Ethernet network interface card to an Intel TOE Gigabit Ethernet NIC, the speed effects become highly demonstrable — even for clients that use older SMB and non-Windows TCP/IP communications stacks.

This change cut CPU utilisation (as measured by Perfmon) during our TCP SYN distributed DoS assault test from 48% to 18%, and in our TCP connections test from 61% at peak to 16% at peak.

We also assaulted the network side of Windows 2008 and IIS7 with a simple test get/post test that emulates a large number of users with get/post requests via http for delivery of static pages. We were able to increase the number of gets (using two independent Gigabit Ethernet connections concurrently) by 32% on the same hardware with Windows 2008 Server over Windows Server 2003.

Microsoft has revamped its web server management application, IIS Manager, removing past administrative obscurities and adding support for multiple site hosting. Web server management can now be performed over HTTP, so that remote administration can be done from a browser.

IT managers can also delegate IIS controls to local administrators or web-development teams, if desired. It's also possible for administrators to 'surgically' lock specific files, rather than give blanket access to configuration files or static page configurations, an administrative boon.

And instead of installing all features by default (and having some of them required to be running even if they're never used), IIS 7 allows administrators to install only necessary modules (there are more than 40 of them). This reduces the attack profile of IIS 7 dramatically.

In all, controls for IIS have been almost reborn.

The consolidation of Active Directory services into three distinct groupings — Active Directory Domain Services, AD Certificate Services, and Active Directory Federated Services — gives administrators the ability to use fewer Active Directory components and plug-ins to manage diverse network needs.

Terminal Services can now be encrypted with Transport Layer Security so that conversations can't be captured from network wires and re-assembled. It can also present applications through http transports that look as though they were running on our desktops as native applications (we used Microsoft Office). Terminal Services configuration is simpler, with more capacity to control printing.

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