DNS-over-HTTPS

Client and server software to query DNS over HTTPS, using Google DNS-over-HTTPS protocol and IETF DNS-over-HTTPS (RFC 8484).

Guide

Tutorial to setup your own DNS-over-HTTPS (DoH) server. (Thanks to Antoine Aflalo)

Installing

From Source

Install Go, at least version 1.10.

(Note for Debian/Ubuntu users: You need to set $GOROOT if you could not get your new version of Go selected by the Makefile.)

First create an empty directory, used for $GOPATH:

mkdir ~/gopath
export GOPATH=~/gopath

To build the program, type:

make

To install DNS-over-HTTPS as Systemd services, type:

sudo make install

By default, Google DNS over HTTPS is used. It should work for most users (except for People's Republic of China). If you need to modify the default settings, type:

sudoedit /etc/dns-over-https/doh-client.conf

To automatically start DNS-over-HTTPS client as a system service, type:

sudo systemctl start doh-client.service
sudo systemctl enable doh-client.service

Then, modify your DNS settings (usually with NetworkManager) to 127.0.0.1.

To test your configuration, type:

dig www.google.com

If it is OK, you will see:

;; SERVER: 127.0.0.1#53(127.0.0.1)

Uninstall

To uninstall, type:

sudo make uninstall

The configuration files are kept at /etc/dns-over-https. Remove them manually if you want.

Using docker image

docker run -itd --name doh-server \
    -p 8053:8053 \
    -e UPSTREAM_DNS_SERVER="udp:8.8.8.8:53" \
    -e DOH_HTTP_PREFIX="/dns-query"
    -e DOH_SERVER_LISTEN=":8053"
    -e DOH_SERVER_TIMEOUT="10"
    -e DOH_SERVER_TRIES="3"
    -e DOH_SERVER_VERBOSE="false"
satishweb/doh-server

Server Configuration

The following is a typical DNS-over-HTTPS architecture:

+--------------+                                +------------------------+
| Application  |                                |  Recursive DNS Server  |
+-------+------+                                +-----------+------------+
        |                                                   |
+-------+------+                                +-----------+------------+
| Client side  |                                |      doh-server        |
| cache (nscd) |                                +-----------+------------+
+-------+------+                                            |
        |         +--------------------------+  +-----------+------------+
+-------+------+  |    HTTP cache server /   |  |   HTTP service muxer   |
|  doh-client  +--+ Content Delivery Network +--+ (Apache, Nginx, Caddy) |
+--------------+  +--------------------------+  +------------------------+

Although DNS-over-HTTPS can work alone, a HTTP service muxer would be useful as you can host DNS-over-HTTPS along with other HTTPS services.

HTTP/2 with at least TLS v1.3 is recommended. OCSP stapling must be enabled, otherwise DNS recursion may happen.

Configuration file

The main configuration file is doh-client.conf.

Server selectors. If several upstream servers are set, one is selected according to upstream_selector for each request. With upstream_selector = "random", a random upstream server will be chosen for each request.

# available selector: random (default) or weighted_round_robin or lvs_weighted_round_robin
upstream_selector = "random"

Example configuration: Apache

SSLProtocol TLSv1.2
SSLHonorCipherOrder On
SSLCipherSuite ECDH+AESGCM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:DH+AES:ECDH+3DES:DH+3DES:RSA+3DES:!aNULL:!MD5:!DSS:!eNULL:!EXP:!LOW:!MD5
SSLUseStapling on
SSLStaplingCache shmcb:/var/lib/apache2/stapling_cache(512000)

<VirtualHost *:443>
    ServerName MY_SERVER_NAME
    Protocols h2 http/1.1
    ProxyPass /dns-query http://[::1]:8053/dns-query
    ProxyPassReverse /dns-query http://[::1]:8053/dns-query
</VirtualHost>

(Credit: Joan Moreau)

Example configuration: Nginx

server {
    listen       443 ssl http2 default_server;
    listen       [::]:443 ssl http2 default_server;
    server_name  MY_SERVER_NAME;

    server_tokens off;

    ssl_protocols TLSv1.2 TLSv1.3;          # TLS 1.3 requires nginx >= 1.13.0
    ssl_prefer_server_ciphers on;
    ssl_dhparam /etc/nginx/dhparam.pem;     # openssl dhparam -dsaparam -out /etc/nginx/dhparam.pem 4096
    ssl_ciphers EECDH+AESGCM:EDH+AESGCM;
    ssl_ecdh_curve secp384r1;               # Requires nginx >= 1.1.0
    ssl_session_timeout  10m;
    ssl_session_cache shared:SSL:10m;
    ssl_session_tickets off;                # Requires nginx >= 1.5.9
    ssl_stapling on;                        # Requires nginx >= 1.3.7
    ssl_stapling_verify on;                 # Requires nginx => 1.3.7
    ssl_early_data off;                     # 0-RTT, enable if desired - Requires nginx >= 1.15.4
    resolver 1.1.1.1 valid=300s;            # Replace with your local resolver
    resolver_timeout 5s;
    # HTTP Security Headers
    add_header X-Frame-Options DENY;
    add_header X-Content-Type-Options nosniff;
    add_header X-XSS-Protection "1; mode=block";
    add_header Strict-Transport-Security "max-age=63072000";
    ssl_certificate /path/to/your/server/certificates/fullchain.pem;
    ssl_certificate_key /path/to/your/server/certificates/privkey.pem;
    location /dns-query {
        proxy_pass       http://localhost:8053/dns-query;
        proxy_set_header Host      $host;
        proxy_set_header X-Real-IP $remote_addr;
    }
}

(Credit: Cipherli.st)

Example configuration: Caddy

https://MY_SERVER_NAME {
        log     / syslog "{remote} - {user} [{when}] \"{method} {scheme}://{host}{uri} {proto}\" {status} {size} \"{>Referer}\" \"{>User-Agent}\" {>X-Forwarded-For}"
        errors  syslog
        gzip
        proxy   /dns-query      http://[::1]:18053 {
                header_upstream Host {host}
                header_upstream X-Real-IP {remote}
                header_upstream X-Forwarded-For {>X-Forwarded-For},{remote}
                header_upstream X-Forwarded-Proto {scheme}
        }
        root    /var/www
        tls {
                ciphers ECDHE-ECDSA-WITH-CHACHA20-POLY1305 ECDHE-RSA-WITH-CHACHA20-POLY1305 ECDHE-ECDSA-AES256-GCM-SHA384 ECDHE-RSA-AES256-GCM-SHA384 ECDHE-ECDSA-AES128-GCM-SHA256 ECDHE-RSA-AES128-GCM-SHA256
                curves  X25519 p384 p521
                must_staple
        }
}

Example configuration: Docker Flow Proxy + Docker Swarm

version: '3.7'
networks:
  default:
    driver: overlay
    attachable: true
    external: false
  proxy:
    external: true
services:
  swarm-listener:
    image: dockerflow/docker-flow-swarm-listener:latest
    hostname: swarm-listener
    init: true
    networks:
      - default
      - proxy
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    environment:
      - DF_NOTIFY_CREATE_SERVICE_URL=http://proxy:8080/v1/docker-flow-proxy/reconfigure
      - DF_NOTIFY_REMOVE_SERVICE_URL=http://proxy:8080/v1/docker-flow-proxy/remove
    deploy:
      placement:
        constraints:
          - node.role==manager
      restart_policy:
        condition: any
        delay: 10s
        max_attempts: 99
        window: 180s
    healthcheck:
      test: [ "CMD", "wget", "http://localhost:8080/v1/docker-flow-swarm-listener/ping", "-O", "/dev/null" ]
      interval: 2m
      timeout: 1m
      retries: 3
  proxy:
    image: dockerflow/docker-flow-proxy:latest
    hostname: proxy
    init: true
    networks:
      - default
      - proxy
    ports:
      - 80:80
      - 443:443
    volumes:
      - ./data/proxy/certs:/certs
    environment:
      TINI_SUBREAPER: 1
      LISTENER_ADDRESS: swarm-listener
      MODE: swarm
      COMPRESSION_ALGO: gzip
      COMPRESSION_TYPE: text/css text/html text/javascript application/javascript text/plain text/xml application/json
      CONNECTION_MODE: http-keep-alive
      DEBUG: "true"
      HTTPS_ONLY: "true"
      STATS_URI: /stats
      EXTRA_FRONTEND: http-request set-log-level debug,http-response set-log-level debug,capture request header User-Agent len 64,acl is_vd path -i /dns-admin,http-request redirect scheme https drop-query append-slash if is_vd,http-response set-header X-Frame-Options DENY,http-response set-header X-Content-Type-Options nosniff,
      EXTRA_GLOBAL:
      SSL_BIND_OPTIONS: no-sslv3 no-tls-tickets no-tlsv10 no-tlsv11
      SSL_BIND_CIPHERS: EECDH+AESGCM:EDH+AESGCM
    deploy:
      replicas: 1
      restart_policy:
        condition: any
        delay: 10s
        max_attempts: 99
        window: 180s
    healthcheck:
      test: [ "CMD", "sh", "-c", "/usr/local/bin/check.sh"]
      interval: 2m
      timeout: 1m
      retries: 3

  doh-server:
    image: satishweb/doh-server
    # Docker Image based on https://github.com/m13253/dns-over-https
    hostname: doh-server
    networks:
      - default
    environment:
      DEBUG: "0"
      UPSTREAM_DNS_SERVER: "udp:YOUR-DNS-SERVER-IP:53"
      DOH_HTTP_PREFIX: "/dns-query"
      DOH_SERVER_LISTEN: ":8053"
      DOH_SERVER_TIMEOUT: "10"
      DOH_SERVER_TRIES: "3"
      DOH_SERVER_VERBOSE: "true"
      # You can add more variables here or as docker secret and entrypoint
      # script will replace them inside doh-server.conf file
      # Entrypoint script source is at https://github.com/satishweb/docker-doh
    volumes:
      # If you want to use your custom doh-server.conf, use below volume mount.
      # - ./doh-server.conf:/server/doh-server.conf
      # Mount app-config script with your customizations
      # - ./app-config:/app-config
    deploy:
      replicas: 1
      restart_policy:
        condition: any
        delay: 10s
        max_attempts: 99
        window: 180s
      labels:
        - com.df.notify=true
        - com.df.distribute=true
        - com.df.servicePath='/dns-query'
        - com.df.port=8053

Above example needs you to add your chained SSL certificate in folder: ./data/proxy/certs and configure upstream DNS server address.

Complete Docker Stack with DFProxy + Lets Encrypt SSL: https://github.com/satishweb/docker-doh

Docker Flow Proxy: https://github.com/docker-flow/docker-flow-proxy

No IPV6 Support: Docker Swarm does not support IPV6 as of yet. Issue is logged here

DNSSEC

DNS-over-HTTPS is compatible with DNSSEC, and requests DNSSEC signatures by default. However signature validation is not built-in. It is highly recommended that you install unbound or bind and pass results for them to validate DNS records.

EDNS0-Client-Subnet (GeoDNS)

DNS-over-HTTPS supports EDNS0-Client-Subnet protocol, which submits part of the client's IP address (/24 for IPv4, /56 for IPv6 by default) to the upstream server. This is useful for GeoDNS and CDNs to work, and is exactly the same configuration as most public DNS servers.

Keep in mind that /24 is not enough to track a single user, although it is precise enough to know the city where the user is located. If you think EDNS0-Client-Subnet is affecting your privacy, you can set no_ecs = true in /etc/dns-over-https/doh-client.conf, with the cost of slower video streaming or software downloading speed.

To ultilize ECS, X-Forwarded-For or X-Real-IP should be enabled on your HTTP service muxer. If your server is backed by unbound or bind, you probably want to configure it to enable the EDNS0-Client-Subnet feature as well.

Protocol compatibility

Google DNS-over-HTTPS Protocol

DNS-over-HTTPS uses a protocol compatible to Google DNS-over-HTTPS, except for absolute expire time is preferred to relative TTL value. Refer to json-dns/response.go for a complete description of the API.

IETF DNS-over-HTTPS Protocol

DNS-over-HTTPS uses a protocol compatible to IETF DNS-over-HTTPS (RFC 8484).

Supported features

Currently supported features are:

• IPv4 / IPv6
• EDNS0 large UDP packet (4 KiB by default)
• EDNS0-Client-Subnet (/24 for IPv4, /56 for IPv6 by default)

The name of the project

This project is named "DNS-over-HTTPS" because it was written before the IETF DoH project. Although this project is compatible with IETF DoH, the project is not affiliated with IETF.

To avoid confusion, you may also call this project "m13253/DNS-over-HTTPS" or anything you like.

License

DNS-over-HTTPS is licensed under the MIT License. You are encouraged to embed DNS-over-HTTPS into your other projects, as long as the license permits.

You are also encouraged to disclose your improvements to the public, so that others may benefit from your modification, in the same way you receive benefits from this project.