Help w/fail2ban in an Nginx jail?

[catnas]

Could someone please help out with getting fail2ban working in a jail with Nginx? My FreeNAS is not exposed to the internet, but I do have an nginx jail that is accessible and it's getting constantly hammered by robots/spam/etc looking for vulnerabilities. I'd like to use fail2ban to stop it. I am comfortable with most of the steps, but it looks like I need to mess with the firewall in the jail to deny the requests identified by fail2ban, and that's where I start to get uncomfortable. If someone would be willing to just post a quick walkthrough of the steps (and locations of the different config files), I'd appreciate it. Thanks