On 3 Nov 2020, at 10:51, Emeric Brun <eb...@haproxy.com> wrote: > >> […] >> >> We are requesting the community and experienced users of DNS servers to >> share their thoughts about this. > > sub-questions are about modern DNS servers: > - do they support DNS over TCP? > - do they support persistent connections with pipelined requests? >
a) Yes, DNS over TCP is in fact pretty much mandatory nowadays and every modern DNS server should support it. Some DNS servers also support DNS over TLS. In fact, some queries (AXFR/IXFR) are always TCP. b) Yes, but that’s recent addition as per RFC 7766 and AFAIK only Bind 9, PowerDNS and Unbound support it but I am honestly not sure if there are others supporting that feature. Historically there were also some security issues considering concurrent tcp clients limits like CVE-2019-6477 in early implementations. My apologies if I have missed to mention anything, I am not up to date with current DNS changes as I used to be. Kind regards, D. -- Dinko Korunic ** Standard disclaimer applies ** Sent from OSF1 osf1v4b V4.0 564 alpha
