Probably better to link to the stackoverflow you quite possibly copied this from so that people can see discussion / alternatives, etc: https://serverfault.com/questions/128069/how-do-i-prevent-ap...

See also the nginx question: https://stackoverflow.com/questions/2999353/how-do-you-hide-...

Note, if you actually did take it from the stackoverflow, you just infringed on someone's copyright; SO's user content is 'creative commons, attribution required'.

Edit: Thanks for adding the attribution, all clear with copyright now :)