how to redirect site/post_name/feed to site/feed

Hi All,

I use 404 error logger on my blog and one typical error i recieve every day is people / bot trying to hit
http://site_name/post_title/feed
which obviously results in error.

I wanted to redirect them to http://site_name/feed/

can any one suggest how.

also can any one suggest is this right or i should do something else.