Make fail2ban report its bans to a community blacklist

Make fail2ban report its bans to a community blacklist

Check the auth log on any server with port 22 open and it's always the same story: endless login attempts from IPs that have clearly done this before. fail2ban bans them, the bantime runs out, and that's it. Nothing learned, nothing shared.

A while ago I started sending those bans to a shared blacklist instead of letting them disappear. I use the one on bl.ipwhois.net, mostly because it needs no signup and no API key. You get 500 requests a day per source IP, which is plenty for a normal server.

Checking an address looks like this:

curl "https://bl.ipwhois.net/api/check?ip=203.0.113.5"