sshguard on FreeBSD
Here’s what you need to do (FreeBSD 10.1):
cd /usr/ports/security/sshguard && make install
insert into pf.conf, modifying for the correct interface name:
table <sshguard> persist block in quick on vtnet0 proto tcp from <sshguard> to any port 22 label "ssh bruteforce"
insert into rc.conf:
To show the contents of the resulting pf table:
sudo pfctl -t sshguard -T show
p.s. Thanks to RS for the pointer.