If you want to try out DNS-over-TLS using the getdns API as proposed in draft-hzhwm-start-tls-for-dns-01 then instructions are listed below.
DNS-over-TLS in getdns 0.1.8
In the 0.1.8 release of getdns there is an experiment implementation of DNS-over-TLS. It is enabled by using one of the following options as the getdns_transport_t value in the getdns_context_set_dns_transport() method:
- This implementation is hard-coded to attempt to connect to the upstream server on port 1021 for TLS. It uses TLS v1.2 only (no SSL).
- These two transport values are not yet fully supported for
- recursive mode or
- for stub mode queries that use any of the DNSSEC extensions.
If used in these cases getdns will currently use TCP without attempting TLS.
- No authentication is done in this implementation with regard to the certificate presented by the upstream server.
- IPv6 support (haven't tested this yet).
- It is planned to add STARTTLS as an option in the next release.
- Note that the transport options available in the API are under review and are likely to change to better support flexible fallback mechanisms and options for TCP/TLS/STARTTLS.
Open resolver hosted by NLNetLabs:
- NLNetLabs is kindly hosting an open resolver that is configured to support DNS-over-TLS on port 1021 for testing purposes.
- IP address: 184.108.40.206 and 2a04:b900:0:100::38
- The server key file can be obtained by contacting email@example.com
Public NSD server hosted by Verisign:
- Verisign Labs are kindly hosting a zone on a server running NSD patched to support DNS-over-TLS on port 1021 for testing purposes
The zone is named starttls.verisignlabs.com and it has A, AAAA, and TXT records for names from 'A' to 'Z'.
The IP address of the server is currently 220.127.116.11.
Server key file is available to download here: nsd.key
The zone is signed
- The server also support TCP fast open
How to Decode TLS packets in Wireshark
If you want to decode the DNS packets in Wireshark (use 1.12.1 or later) to get support TLSv1.2
You can also watch a short video demonstrating TCP connection re-use, pipelining, TCP Fast Open and DNS-over-TLS: DNS-over-TLS demo video