Cisco Firepower 1010 Getting Started Guide
IPFW is the built-in firewall in FreeBSD. Powerful and easy to configure this article is a starting point into managing it.
[I tried this cookbook as-is, and it blocked everything on the first try, because I left out the firewall_type parameter. It didn't seem like "workstation" makes sense for a server, but the only other one that applies rules only to the current node is "client" which sounds even less like a server.]
IPBan: https://www.digitalruby.com/ipban/ [Windows/Linux only]
SSHguard: http://www.sshguard.net
Sentry? https://github.com/msimerson/sentry/ [Perl, not sure how automated it is]
Cisco ASA 5506-X Series Quick Start Guide -Quick Start Guide: Cisco ASA 5506-X Series Quick Start Guide
This is how the RedHat branch ruined iptables. In my default config, there were no interfaces in the default zone, making configuring it a guessing game.