  The Domain Name System (DNS) comprises name servers translating domain names
into, commonly, IP addresses. Authoritative name servers hosts the resource
records (RR) for certain zones, and resolver name servers are responsible for
querying and answering DNS queries on behalf of their clients. Unfortunately,
cybercriminals often use DNS for malicious purposes, such as phishing, malware
distribution, and botnet communication. To combat these threats, filtering
resolvers have become increasingly popular, employing various techniques to
identify and block malicious requests. In this paper, we survey several
techniques to implement and enhance the capabilities of filtering resolvers
including response policy zones, threat intelligence feeds, and detection of
algorithmically generated domains. We identify the current trends of each area
and find missing intersections in the literature, which could be used to
improve the effectiveness of filtering resolvers. In addition, we propose
future work designing a framework for filtering resolvers using
state-of-the-art approaches identified in this study.
