As foreseen, I am pleased how others have contributed to and evolved this mini project:
- Supports both IPv6 and IPv4
- ipset rather than iptables
- state files no longer required.
https://gist.github.com/klepsydra/ecf975984b32b1c8291a#gistcomment-1645349
Yet when originally searching for a missing solution--and later developing one--to https://serverfault.com/questions/647891/make-fail2ban-use-public-blacklists/648087#648087 (Subsequently shared back to this very same SE), a wildly different response came about from a few particular members at the time on Serverfault, championed by one's subjective non-expert reactions.
Diplomacy aside, this is not meant to step on anyone's toes. But in my opinion, as others have eventually noted too, this question should not have been closed. At least not so quickly and prematurely, before expertise in the field would have had a crack at it. Technology has since progressed, and hopefully the community on this particular SE had matured a bit too. I wonder if such a question can be re-opened and the voting damage undone, of the original question having fallen victim to the lynch-mob effect, despite being well-researched in advance and clear and relevant.