This table lists the best understanding of the current status of DNS-over-TLS related features in the latest stable releases of a selection of open source DNS software.
If there are errors or glaring omission please email firstname.lastname@example.org
This works with a couple of provisos:
Work in progress
using patched LDNS
Also tested OK against PowerDNS,
Knot and Yadifa
Attempting to understand
limitations/issues around queue sizes,
number of outstanding packets etc.
See the DNS Privacy reference material page for more details on the individual features.
|TCP fast open(b)|
|Connection reuse (Q/R, Q/R, Q/R)|
Pipelining of queries(Q,Q,Q,R,R,R)
|Process OOOR (Q1,Q2,R2,R1)||n/a|
|TLS encryption (Port 853)|
|TCP fast open**|
Process Pipelined queries
|TLS encryption (Port 853)||(d)|
|Provide TLS auth credentials||(d)|
|TLS DNSSEC Chain Extension|
|EDNS0 Padding (basic)|
(a) getdns uses libunbound in recursive mode
(b) not yet available on Windows
(c) Implies robust TCP connection management (see RFC7828 and RFC7766)
(d) See this article for how to use stunnel with BIND to provide DNS-over-TLS - thanks Francis Dupont!
Note pipelining and OOOP are not applicable for synchronous applications.