Implementation Status

This table lists the best understanding of  current status of DNS-over-TLS related features in the latest stable releases of a selection of commonly used DNS software.

If there are errors of glaring omission please email sara@sinodun.com 

Coming soon will be guides on how to use NGINX and other proxies to provide DNS-over-TLS, also see here.

See the DNS-over-TLS reference material page for more details on the indivudual features. 

Clients

Mode

Stub 

Recursive resolver

Software

ldns

(drill)

digit

getdns

BIND

(dig)

getdns(a)

UnboundBIND

Knot

Res

 

 

TCP/TLS Features

TCP fast open(b) (tick)

(tick)

 

P

  (tick)
Connection reuse (Q/R, Q/R, Q/R) (tick)

(tick)

(tick)  (tick)(tick)

Pipelining of queries(Q,Q,Q,R,R,R)

n/a(tick)

(tick)

(tick)  (tick)(tick)
Process OOOR (Q1,Q2,R2,R1)n/a (tick)

(tick)

(tick)  (tick)(tick)
EDNS0 Keepalive(c)  (tick)     

 

 

TLS Features

TLS encryption (Port 853) (tick)(tick) (tick)(tick)(d) 
TLS authentication  (tick)     
EDNS0 Padding  (tick)     

Servers

ModeRecursiveAuth
Software

Unbound

BIND

Knot

Res

NSDBIND

Knot

Auth

 

TCP/TLS Features

TCP fast open**  (tick)  (tick)

Process Pipelined queries

(tick)(tick)(tick)(tick)(tick)(tick)
Provide OOORWIP(tick)(tick)n/an/an/a
EDNS0 Keepalive***WIP     

 


TLS Features

TLS encryption (Port 853)(tick) WIP   
Provide TLS auth credentials(tick) WIP   
EDNS0 Padding      

 

KEY:

(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.