 Let's now conclude with a summary of what we have seen during this week. We have discussed the basic mechanisms behind net or scans and review a group of different scan types. We have also given examples of scans either seen in the wild, one for SSH dictionary attack and one for an internet wide scan conducted by the Sality Botnet. Finally, we have pointed out that scans can also be considered a form of active measurements and they are at time used in research studies. The external material provided for worms cover the beginning and the rise of worms and show how worms can spread and can be modeled. Also give insight into some case studies. The lecture on peer-to-peer botnets by Christian Rossell explains how peer-to-peer botnet works, with a focus on how it is possible to monitor this type of botnet, for example to find the botnet population. Then the talks cover possible counter-measures, like poisoning, partitioning and sink-holing.