The Domain Name System (DNS) is one of the most critical services for the daily operation of the Internet. It is used to primarily resolve names to IP addresses and vice versa on the Internet through a distributed hierarchical system. This work aims at characterizing the authoritative DNS nameservers of two categories of the domain publicly available in-addr.arpa and ip6.arpa reverse zones managed by AFRINIC, 57 ccTLDs in the African region.
We study several aspects such as the number of nameservers, the geographical and topological distribution, EDNS and TCP compliance. Overall, the authoritative servers of reverse zones of IP addresses allocated by AFRINIC to their members are 75% EDNS compliant and 72% TCP compliant while the authoritative servers of Africa ccTLDs are respectively 46% and 43.6% compliant for EDNS and TCP. The study also revealed other important information such as the clear domination of some authoritative nameservers, which represents a potential risk of service disruption should these servers become unavailable.
Similarly, the geographic location of the authoritative nameservers may potentially have an impact on response times to DNS resolutions and affect user experience. Therefore, a series of efforts must be done in those areas to ensure the optimal functioning of the Internet in the region.