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I've setup a wildcard CNAME entry as an alias for one of my servers that looks like this: 

*.custom.example.my.home

When I try to resolve matching entries without specifying the domain (e.g. asdf.custom) I get different behaviours from OS X, Linux and Windows. So just to clarify for all these OSs specifying the fully qualified domain name (e.g. asdf.custom.example.my.home) will lead to a successful lookup.

For Linux and OS X the specified DNS search suffixes are tried as expected, so the entries are resolvable, ping works, the webserver running on the server can be reached whereas in Windows none of these simple networking operations work.

PS C:\Users\> ping asdf.custom
Ping request could not find host asdf.custom Please check the name and try again.
PS C:\Users\> .\nslookup.exe asdf.custom
Server:         192.168.X.X
Address:        192.168.X.X#53

** server can't find asdf.custom: NXDOMAIN

What I suspect is that the Windows DNS implementation assumes that finding the dot it is dealing with the absolute name already, while it should actually try to go through the configured DNS suffixes. I'm wondering if there is a setting to instruct it to do so.

I'm observing this behaviour for Windows 7 / Server 2008, but haven't tried anything else.

bfloriang
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  • I've found one article confirming that in some version of Windows, an "unqualified DNS name" is one without "any dots": http://support.simpledns.com/kb/a64/using-unqualified-domain-names-names-with-no-dots.aspx This article confirms for Vista and has a possible registry fix: http://blogs.technet.com/b/networking/archive/2009/04/16/dns-client-name-resolution-behavior-in-windows-vista-vs-windows-xp.aspx – Todd Wilcox Sep 03 '15 at 15:21
  • Actually, see this question: http://serverfault.com/questions/649352/what-are-the-security-implications-of-the-allow-dns-suffix-appending-to-unquali And this has a GPO fix for it: http://superuser.com/questions/809424/windows-dns-suffix-frustration – Todd Wilcox Sep 03 '15 at 15:24
  • Looks like your question may be a duplicate of: http://serverfault.com/questions/224325/issues-resolving-local-domain-name-with-windows-7 – Todd Wilcox Sep 03 '15 at 15:27
  • @Todd Wilcox: I think you're right. This does answer my question. I didn't see the other question and had my mind fixed too much on wildcard DNS resolution. – bfloriang Sep 03 '15 at 15:37

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