A fail2ban lite. IPQ BDB is a netfilter userspace daemon that can block or mark IP packets according to iptables rules that issue the corresponding -j NFQUEUE, as well as a Berkeley database of bad IPv4 addresses. A log parser and a banning utility add entries to the database. An IP has to be caught a configurable number of times before being blocked. Transitions between blocked and non-blocked are faded using probabilities. A halving period governs IP rehabilitation.