If you have a customer and DNS seems to work strangely, have a look if you don't have a so called single-label domain for Active Directory, such as host1.intern

If you have a customer and DNS seems to work strangely, have a look if you don't have a so called single-label domain for Active Directory, such as host1.internal or crusty.internal if you have more creative admins or even worse, db.local. On Windows, the name resolution on single-label domains behaves a bit differently, using NetBIOS resolution which can prevent you from e.g. adding a new host to the domain from a different subnet - you might see this as DNS failure. Of course, it is not DNS's fault, if it wasn't asked in the first place. Here are some more details: https://support.microsoft.com/en-us/help/300684/deployment-and-operation-of-active-directory-domains-that-are-configur https://support.microsoft.com/en-us/help/300684/deployment-a... and https://admx.help/?Category=Windows_10_2016&Policy=Microsoft.Policies.NetLogon::Netlogon_AllowSingleLabelDnsDomain https://admx.help/?Category=Windows_10_2016&Policy=Microsoft... which does the DNS resolution even for these less than ideal domains.