Setup fail2ban to block people who hit the Clojars repo too much

[danielcompton]

There are some people with misconfigured applications/Nexus repo's who request files way too much. It could be good to use fail2ban to stop them from making requests too often. A first approximation for detecting this would be to check for IP's downloading the same file more than 5 times in half an hour. There are a few things to consider here:

• The larger the time window, the more memory this will consume
• If we're going to move to a CDN, how will we handle misconfigured clients like this? Maybe we can analyse the logs and block IPs out of band?
• We don't want to block normal users, it should probably be run in report only mode for a while to make sure it's calibrated correctly.
• It would be good to build up profiles of what normal maven usage and abusive behaviour look like, as kicking off a build with a clean m2 will generate a lot of (valid) requests.

http://codelog.climens.net/2011/02/13/using-fail2ban-with-nginx-in-debian/
http://blog.teabough.com/fail2ban-api-mailjet/