DFS have never been officially supported even though I my experience have not had any problems. But now there is issues if you use an AutoCAD 2010 product.
Knowledge Base document: Distributed File System (DFS) Problems in AutoCAD 2010
IssueYou are experiencing problems with AutoCAD 2010 (or a vertical product based on AutoCAD 2010) not working with DFS.
Although Autodesk does not officially support using the Windows Distributed File System with AutoCAD and AutoCAD-based vertical products, it has been known to work properly in the past and many customers use DFS with our products. We have recently identified two separate issues that can affect DFS usage.
The first problem is the inability to open a DFS folder from the File Navigation dialog in AutoCAD 2010. This problem has been corrected in Update 1 for AutoCAD 2010. If you are using AutoCAD LT 2010, or a vertical product, you should apply the Update for that product that includes Update 1 from AutoCAD. For most vertical products, that will also be Update 1 however, for AutoCAD Civil 3D, that will be Update 2.
The second problem is the inability to open folders on a DFS share by double-clicking. This is mostly seen on Vista SP2 and Windows 7 and is due to changes Microsoft made in those operating systems to change a folder to a link. For file folders that won’t open using double-click, the recommended work-around is to pick the Open button instead.
Link pasted with this Autodesk KB plugin for Live Writer.