Very simple guide to using ufw to create firewall rules. `ufw allow ssh/tcp && ufw allow http/tcp && ufw allow https/tcp && ufw enable && ufw status` done. :-)
A python traffic shaper that can control network usage on a local machine by a number of useful factors including individual programs and so on. Could be very handy on satellite / edge / grps roaming.
DenyHosts blocks hosts after several failed login attempts. It also provides a subscription service where you can share hosts that you block, so as to block attackers before they try the first login.