DNS resolution issue only on my mac air

Hi all,

need some help...

I have a Mac air running 10.9.3.

I'm having serious problems when at home as it seems that everytime I connect to my wifi, after a few minutes the mac and the router aren't able to resolve dns anymore so I have to refresh the IP of the router from my ISP through the router's web admin page (D-link DIR-865 L).

I've tried multiple things:

- renewing only the ip lease of my mac from the router's dhcp server - doesn't work

- assigning static dns servers to both mac and router (opendns, google) individually and separately (one at a time) - doesn't work

- changing wifi band from 2,5 Mhz to 5Mhz etc - doesn't work

- changing channels - doesn't work

Basically there is no improvement whatever I try and this is getting totally annoying and impossible to use. I did try calling my ISP and went through router reconfig, reset etc etc. doesn't work.

The strange thing is that I have iphone's, ipad's, a dell laptop, an old macbook, another Mac Air (my wife's - running same osx version) and the issue appears ONLY when I connect my own Mac... the issue is that after the DNA resolution error happens, no device is able to resolve any address and i have to refresh the router's (WAN) IP address from the ISP.

Any help is highly appreciated!

thanks