Definition - What does Bogon Filtering mean?
Techopedia explains Bogon Filtering
Bogons are often considered illegitimate in terms of Internet address prefixes or components. To that end, bogon filtering is one way to filter out traffic that may be illegitimate or even dangerous.
Various firewalls and other tools use bogon filtering to eliminate these kinds of often harmful addresses, and Internet service providers may offer this kind of service to users.
The name bogon has its roots in the words 'bogus’ and 'bogosity’ and is a generally accepted part of IT slang.