After a week of housekeeping I thought I'd walk through a real-world example of BOGON filtering. We're using a number of systems and platforms, none of it is relevant to the actual requirement or result.
The point here is to take a list of 'Dubious Internet Sources' and dump them at your provider edge. It may not be perfect but it does free up a lot of manual effort.
BOGON Source: https://www.team-cymru.com/bogon-refe...
QUAGGA Configuration: https://www.team-cymru.com/bgp-exampl...
RESERVED IP Space RFC: https://tools.ietf.org/html/rfc6598