There is no cross-platform standard for keeping a fast search index up to date on a server.
OS X Server has a Spotlight server feature to allow OS X clients to do fast Spotlight searches of the server's files, but Windows doesn't have a native client for it, and Apple doesn't provide a Windows client for it.
There are third party products from companies like HELIOS that provide solutions to this problem.
Here's HELIOS's solution. If you do a bit of searching, you can probably find other third-party commercial solutions.