I've been struggling with a wireless SBG900 for a couple of hours now. The interface looks fine (as far as wireless router interfaces go) and I had the simple setting up WPA security on this router. The higher security setting was supposed to replace the current no password + MAC restriction setup. The bottom line is that after removing the registered MAC addresses the router simply refused connections from all clients. And the best part is that nowhere in the interface I could find a clicky button to enable it. [caption id="attachment_145" align="aligncenter" width="595" caption="There is no place to disable the MAC filter"] [/caption] Tamper Data to the rescue. Click "Apply" and just change the value of the Wireless.EnableAllowAccess.enableAllowAccess parameter to 0. Works fine now.