This update enables the Autodesk Network License Manager to support IPv6 networks using Microsoft® Windows® Server 2008, Windows Vista® 32-bit and Windows Vista® 64-bit, Windows 7 32-bit and Windows 7 64-bit.

Important:

• This version of the Autodesk Network License Manager does not support early return of borrowed licenses.
• This implementation only supports a mixed IPv4 and IPv6 environment. This implementation does not support network license checkouts in an IPv6-only environment.

Knowledge Base document: Autodesk Network License Manager IPv6 Support for Windows

Now we have the better solution for this: Licensing error 1.5.-15 in Network License Manager