Lol I actually looked into this a bit more, seems like no one can make their minds! It is strange though that .local is a valid gtld now.
Microsoft recommendations[edit] The connection of Macintosh and Linux computers or zeroconf peripherals to Windows networks can be problematic if those networks include name servers that use .local as a search domain for internal devices.
At one time, Microsoft at least suggested the use of .local as a pseudo-TLD for small private networks with internal DNS servers, via documents that (as of this writing) are still accessible. For example, support article 296250[2] included the following option:
Make the name a private domain name that is used for name resolution on the internal Small Business Server network. This name is usually configured with the first-level domain of .local. At the present time, the .local domain name is not registered on the Internet. However, more recent articles have cautioned or advised against such use of the .local TLD.
Support article 300684[3] listed contoso.local as an example of a "best-practice Active Directory domain name", but then added:
We recommend that you register DNS names for the top-most internal and external DNS namespaces with an Internet registrar. which would of course preclude using that or any other domain ending with .local.
Microsoft TechNet article 708159[4] suggested .local for the exact opposite reason:
Using the .local label for the full DNS name for the internal domain is a more secure configuration because the .local label is not registered for use on the Internet. This separates your internal domain from your public Internet domain name. but later recommended against it:
If you have Macintosh client computers that are running the Macintosh OS X version 10.3 operating system or later, … it is recommended that you do not use the .local label for the full DNS name of your internal domain. If you must use the .local label, then you must also configure settings on the Macintosh computers so they can discover other computers on the network. For more information about how to configure client computers running Macintosh OS X version 10.3 or later, see “Connecting Macintosh Computers to a Windows Small Business Server 2003 Network” on the Microsoft Web site at [1]. TechNet article 726016[5] cautioned against using .local:
…we do not recommend using unregistered suffixes, such as .local.