PS2 DNAS authentication issue thru wireless

I wasn't sure either if to post this under the game or networking section but its more of a networking issue so I apologize in advance if Im in the wrong section.
I recently bought a D-Link DGL-4300 Gaming router along with the gaming adapter DGL-3420 and I trying to play PS2 with wireless. I'm pretty sure that the adapter needs to be on Infrastructure mode in order to work with my settings since I'm connecting through the router (if I'm mistaken let me know). On the other hand on the router I've set the preset rule that has the required ports in order for the PS2 to work online. With that done when I confifure my PS2 with manual settings (IP,SN,DNS) and test the connection, it passes the test. So when the DNAS authentication screen comes on it stays there for a while and then in prompts error -612 [-612 NET_DNS_TRY_AGAIN The DNS resolver cannot be found. "DNAS Error (-612) A network error has occurred." Please double-check your network connection and/or network configuration.]
What I need to know is if this is a known issue when trying to play PS2 wirelessly or if anyone suggests anything that I might be missing.

Thanks in advance