BFD is a shell script which parses security logs and detects authentication failures. It is a brute force implementation without much complexity, and it works in conjunction with a APF (Advanced Policy-based Firewall).
## Get the latest source and untar.
# cd /usr/src/utils
# wget http://rfxnetworks.com/downloads/bfd-current.tar.gz
# tar xfz bfd-current.tar.gz
# cd bfd-*
Read the README file, and edit the configuration file located in /usr/local/bfd/conf.bfd.
Find ALERT=”0″ and replace it with ALERT=”1″
Find EMAIL_USR=”root” and replace it with EMAIL_USR=”email@example.com”
Edit /usr/local/bfd/ignore.hosts file, and add your own trusted IPs. BFD uses APF and hence it orverrides allow_hosts.rules, so it is important that you add trusted IP addresses to prevent yourself from being locked out.
## Start the program.
# /usr/local/sbin/bfd -s