cd /usr/ports/net-mgmt/p0f && make instal clean

#wget https://mta.org.ua/p0f/db/p0f.fp-3.09b -O/usr/local/etc/p0f.fp
curl -L -o - https://mta.org.ua/p0f/db/p0f.fp-3.09b.diff | patch /usr/local/etc/p0f.fp

wget https://mta.org.ua/p0f/freebsd/usr/local/etc/newsyslog.conf.d/newsyslog-p0f.conf -O/usr/local/etc/newsyslog.conf.d/newsyslog-p0f.conf

echo 'p0f_enable="YES"' >> /etc/rc.conf
echo 'p0f_iface="em0"' >> /etc/rc.conf
echo '#p0f_fingerprint_database="/usr/local/etc/p0f.fp"' >> /etc/rc.conf
echo '#p0f_socket="/var/run/p0f.sock"' >> /etc/rc.conf
echo '#p0f_pidfile="/var/run/p0f.pid"' >> /etc/rc.conf
echo '#p0f_flags="-o /var/log/p0f.log"' >> /etc/rc.conf

wget http://mta.org.ua/p0f/freebsd/usr/local/etc/rc.d/p0f -O/usr/local/etc/rc.d/p0f
chmod +x /usr/local/etc/rc.d/p0f

service p0f start