Toggle DNS Check seems to be confusing word but after drilling down you will notice that its same as allowing auto configured DNS ( example and allowing custom DNS (u.x.y.z). In android mobile phones you can easily perform this task as i described earlier in updating SMSC no in Android . You just need to use master testing code for android phones i.e  dial this code from your phone *#*#4636#*#*

Some screen shots of the test performed on Samsung GalaxyS are as follows

Toggle DNS Check

Update DNS Check