Comment 8 for bug 78361

Apparently, the patch-o-matic tarpit module is bit-rotted and unmaintained. However, there's a new xt_tarpit module that looks promising:

  http://<email address hidden>/7313437.html

An alternative approach might be to setup labrea (apt-get'able) on a virtual machine, and forward malicious traffic to it. That would at least require more state to be kept, so a kernel-level tarpit is preferable.