I don't want to be picky and lose time on such things if you could spend your time better, anyway, my base idea was something like:

    active_devices.find { |d| set_default_route[_for_wan_device]?(d) }

    def set_default_route[_for_wan_device]?(device)
      do..the..job if wan_dev(d)?
    end

Obviously, `set_default_route` function name sounds quite generic so it should probably just set the default route not only for devices in WAN.

or maybe even `active_devices.find { |d| set_default_route?(d) if wan_dev?(d) }`