 Let's summarize what we have learned about DNS security. First, we have explored cache poisoning attacks, as an example of attacks to the information in the DNS. We have seen several variants of attacks in increasing degree of complexity and gain for attacker. Finally, we have looked at possible mitigation strategies. We have then moved on to discuss situation in which the DNS itself is the target of an attack. We have reasoned about what are the consequence of a successful attack against DNS, and then we have looked into a real event, the attack against the root servers in November and December 2015. Based on this event, we have summarized some mitigation strategies that have been deployed in practice. Finally, we have studied a practical case of possible misuse of the DNS system for malicious goals. We have looked at the DNS stack and the trade-off between adding authenticity and integrity to DNS and the cost of larger responses. And now this can be misused in the context of reflection and anti-implification attacks. We also have seen possible mitigation strategies, such as blocking queries that will type any and move to elliptic curve cryptography, which is more secure than the currently used RSA scheme and also uses smaller keys.