Letters - 29 Oct 2008

Split-Brain DNS
I read Michael Dragone’s “Split-Brain DNS” (September 2008, InstantDoc ID 99772) and found it helpful. However, I have a question about split-brain DNS setup. In my scenario, mydomain.com has an internally hosted web server (WEB01) externally published as www.mydomain.com, as well as an externally hosted web server (WEBSVR05) externally published as webi.mydomain.com. If I use split-brain DNS, I would add only WEB01 to my internal DNS server’s mydomain.com zone. So, calling www.mydomain.com should be resolved by WEB01—by querying the address zone mydomain.com. However, if I call for webi .mydomain.com, my DNS server won’t find it locally and should forward the resolve call to my ISP’s DNS servers and get it resolved there.

As far as I understand the mechanism of a Windows Server 2003 DNS server, that last part won’t happen, right? Or can I manipulate certain settings or configurations to achieve this behavior? If not, once I add an Internet-known zone to my internal DNS server, I’ll need to add (manually) all servers to this zone. Or can I get a list of all servers of a domain known on the Internet, then import them into the flat file of the new zone (automatically)?

I’m looking for ways to resolve hostnames in domains where we have some servers hosted internally and some hosted externally (with a hosting company).

—Marc Engrie

In the situation you’ve outlined, you’re correct. The DNS server wouldn’t forward the query for webi.mydomain.com to your ISP’s DNS servers. Note that this behavior isn’t specific to the Windows DNS server; it would happen with any DNS server. This situation occurs because the mydomain.com zone is present on the DNS server, making it able to authoritatively answer queries for any host in the mydomian.com zone.

Once you set up my domain.com on your internal DNS server, you’ll need to add the appropriate A records for externally hosted hosts. Have the hosting company send you a copy of the zone file. You’ll have to edit it to add A records for your internally hosted hosts.

—Michael Dragone

Thurrott Man-Crush
I read Christan Humphries’ “Relieve Your SharePoint Pressure Points” (September 2008, InstantDoc ID 99776). The article was informative, well written, and fun to read. I’m looking forward to more from Christan. I’ve subscribed to Windows IT Pro off and on for a long time. I get overloaded from time to time, and the unread issues start to pile up, so every now and then I back off for a while. But the magazine is too good to be away from for too long. I also have a huge man-crush on Paul Thurrott and really enjoy his podcasts, emails, tweets, and what-not. Recently, I subscribed again because of him.


Hyper-V FAQs
I read Michael Otey’s Top 10 column, “Hyper-V FAQs” (August 2008, InstantDoc ID 99440). In the 10th FAQ, Michael addresses whether Hyper-V runs like Virtual Server, on top of Windows. Michael’s answer is no. Although all the architecture diagrams I’ve seen agree with his answer, it would have been a good service to readers to clarify that they must first install the Server 2008 OS before installing Hyper-V.

—George Squillace

You’re right. At this time, you still need to install some form of Server 2008 to get Hyper-V. However, Microsoft is planning a standalone version of Hyper-V in the near future.

—Michael Otey

Windows Server 2008 Licensing
I have a question about the sidebar, “Windows Server 2008 Availability and Licensing,” which appeared with Paul Thurrott’s “Windows Server 2008’s Radical New Features” (July 2008, InstantDoc ID 99141). Am I correct in assuming that I can run four virtual instances of the Enterprise edition? Also, if I have a server with VMware ESXi installed and I have a license for Server 2008 Enterprise, can I still use four virtual instances? Or does the license apply only to Hyper-V?

—Virginie Arsenault-Jacques

You’re correct: Server 2008 Enterprise provides a license for an additional four virtualized instances of the Enterprise edition. You can run these instances on any virtualization platform, including VMware ESX.

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