A single engine pilot reports a near miss with a parachute jump aircraft while transiting Dunn Air Park at 4;000'. ATC advised both aircraft about their mutual traffic.

Narrative

I was transiting northbound through the area near Dunn Air Park (X21). In a descent passing 4000 ft MSL we had just passed it on the East side to remain clear of parachute jumping operations. I was getting Flight Following from Orlando Approach and was aware that the jump aircraft had just taken off. Orlando advised him of traffic (me) a couple times. I kept looking for it but didn't see it until it was just off my left; slightly behind and slightly below; climbing and overtaking me. Orlando was in the process of again calling out my aircraft as traffic to the jump aircraft when I saw it. I immediately banked sharply right and turned about 20 deg. As I rolled out I saw the jump aircraft banking left and climbing through my altitude. I believe we saw each other at the same time. Given the geometry involved; I believe the other pilot would have had a better chance of seeing me than of me seeing him. Other than paying 100% attention to looking for the jump aircraft I don't know what else I could have done.