Configured search on SharePoint Foundation 2010, but only some user can get the search results, the others not! Users have different privileges, so it's not the case when search works only with farm admins.
Inspecting SharePoint log, I found this
After googled about the problem, I found this post http://blogs.msdn.com/b/russmax/archive/2010/01/20/why-the-tokengroupsglobalanduniversal-tggau-attribute-matters-in-sharepoint-2010.aspx
There is a group in AD called Pre-Windows 2000 Compatibility Access, I added search service account to this group and search started working properly