problem connecting belkin n600 db to imac27 maverick

Hello!

I've just bought a new Imac27 with maverick, and I found a strange problem connecting it to my Wi-Fi: I'm using a router Belkin N600 db since a couple of year with ipad2 and Iphone 4gs with no problem while the imac see the wan (i'm able to read and copy files from WD mybook live), but I cannot enter in internet!

Does anybody faced this problem, what I can check / set to allow also Imac browse internet?

tnks for any help