DoH Server

An implementation of DNS over HTTPS server, which supports both RFC8484 and dns-json (as same as Cloudflare). The purpose of this project is mostly for learning and personal use.

Credits

• dnsguide for the DNS protocol implementation

Specs

DNS Wireformat

The format is defined in RFC 1035

Using POST

:method = POST
:scheme = https
:authority = localhost
:path = /dns-query
accept = application/dns-message
content-type = application/dns-message
content-length = 33

<33 bytes represented by the following hex encoding>
00 00 01 00 00 01 00 00  00 00 00 00 03 77 77 77
07 65 78 61 6d 70 6c 65  03 63 6f 6d 00 00 01 00
01

Response

:status = 200
content-type = application/dns-message
content-length = 64
cache-control = max-age=128

<64 bytes represented by the following hex encoding>
00 00 81 80 00 01 00 01  00 00 00 00 03 77 77 77
07 65 78 61 6d 70 6c 65  03 63 6f 6d 00 00 01 00
01 03 77 77 77 07 65 78  61 6d 70 6c 65 03 63 6f
6d 00 00 01 00 01 00 00  00 80 00 04 C0 00 02 01

You can change the header accept = application/dns-json to request the server return response in JSON format.

Using GET

When using GET, the DNS query is encoded into the URL using Base64 with URL-safe and no padding.

curl -H 'accept: application/dns-message' -v 'https://localhost/dns-query?dns=q80BAAABAAAAAAAAA3d3dwdleGFtcGxlA2NvbQAAAQAB' | hexdump

JSON

The JSON only support query using GET.

Supported params

• name (required): the query name
• type (required): the query type (e.g. A, AAAA, NS, MX,...)

Example

curl -H "accept: application/dns-json" "https://localhost/dns-query?name=example.com&type=AAAA"

Quickstart

# start dependencies with Docker
make run-deps

# start the server
make run

# resolve example.com
curl -H "accept: application/dns-json" "https://localhost/dns-query?name=example.com&type=AAAA"

# benchmark
make bench