Please see: What is the license for content I post?
As noted in the Stack Exchange Terms of Service and in the footer of every page, all user contributions are licensed under Creative Commons Attribution-Share Alike. Proper attribution is required if you republish any Stack Exchange content.
The site you linked to appears to have hit all the required attribution points, except they linked back to SF with nofollow. Specifically the link "View full answer on Server Fault" is nofollowed.