Washing your knives in the dishwasher will slowly ruin them. Stainless steel is not stainless. Your dishwasher will erode the sharpened edge making them dull and corrode the rivets that hold the handles on. Those brown spots are rust which will turn into pitting.
Wash and dry your cutlery individually by hand.
How to remove rust spots on your knives. http://www.themakeyourownzone.com/2013/10/remove-rust-spots-knives.html