It's BS that the MAC printed on the bottom of the unit is the ethernet and not the wireless.
What I did was temporarily turn off MAC filtering, let the Slingbox connect, then go into the Attached Devices section of the router to see what the MAC of the Slingbox's wireless adapter was. Then I turned MAC filtering back on and put that in the table.
Again, total BS that Sling doesn't put that MAC on the bottom of the unit. Way to bob and weave Slingbox!!