DNS is one of the core building blocks of the Internet. In this paper, we investigate DNS resolution in a strict IPv6-only scenario and find that a substantial fraction of zones cannot be resolved. We point out, that the presence of an AAAA resource record for a zone’s nameserver does not necessarily imply that it is resolvable in an IPv6-only environment since the full DNS delegation chain must resolve via IPv6 as well. Hence, in an IPv6-only setting zones may experience an effect similar to what is commonly referred to as lame delegation. Our longitudinal study shows that the continuing centralization of the Internet has a large impact on IPv6 readiness, i.e., a small number of large DNS providers has, and still can, influence IPv6 readiness for a large number of zones. A single operator that enabled IPv6 DNS resolution–by adding IPv6 glue records–was responsible for around 20.3% of all zones in our dataset not resolving over IPv6 until January 2017. Even today, 10% of DNS operators are responsible for more than 97.5% of all zones that do not resolve using IPv6.@en

Security Operations Centers (SOCs) are in need of automation for triaging alerts. Current approaches focus on analyzing and enriching individual alerts. We take a different approach and analyze the population of alerts. In an observational study over 24 weeks, we find a surprising pattern: some domains get analyzed again and again by different analysts, without coming to a final evaluation. Overall, 19% of the domains trigger 74% of all investigations. The most time-consuming domains are classified as false positives and 'potentially unwanted programs' - the lowest threat level. To increase SOC efficiency, we design DomainPrio, a tool that prioritizes domains that are likely to be the subject of repeated, incomplete investigations. This enables us to indicate to the first analyst encountering this domain that the investigation should be, if possible, completed on this first attempt, so future investigations on the same domain can be prevented. DomainPrio is able to predict these domains with 89% accuracy and does so with an interpretable and auditable logistic regression model. When evaluating our tool on 100 days of data from a production setting, we find that it can potentially reduce the number of alert investigations by up to 35%, presenting the SOC with very substantial efficiency gains. @en