How To Set Up Dnscrypt Proxy For Authenticated Encrypted

DNS encryption is a critical layer of privacy infrastructure. While DoH (DNS over HTTPS) and DoT (DNS over TLS) have gained popularity, DNSCrypt offers an alternative that predates both and provides strong authentication through the DNSCrypt protocol. This guide walks you through setting up DNSCrypt Proxy on Linux, configuring it for authenticated encrypted DNS queries, and verifying that your setup works correctly.

What is DNSCrypt?

DNSCrypt is a protocol that encrypts and authenticates DNS traffic between your client and resolver. Unlike DoH which wraps DNS queries in HTTPS traffic, DNSCrypt uses its own encryption layer with Ed25519 public key authentication. This means you can verify that responses actually come from your chosen resolver and haven’t been tampered with in transit.

The protocol supports both anonymous resolvers (which provide encryption without authentication) and authenticated resolvers (which verify the server’s identity through cryptographic keys). For maximum privacy, authenticated DNSCrypt ensures that even the resolver operator cannot forge DNS responses.

Installing DNSCrypt Proxy

Most Linux distributions include DNSCrypt Proxy in their package managers. On Debian-based systems:

sudo apt update
sudo apt install dnscrypt-proxy

On Arch Linux:

sudo pacman -S dnscrypt-proxy

On Fedora:

sudo dnf install dnscrypt-proxy

If your distribution doesn’t package DNSCrypt Proxy, you can download precompiled binaries from the official GitHub repository:

curl -sL https://github.com/DNSCrypt/dnscrypt-proxy/releases/latest/download/dnscrypt-proxy-linux_arm64.tar.gz | sudo tar xz -C /usr/local/bin/

Replace arm64 with x86_64 for 64-bit Intel/AMD systems.

Configuring DNSCrypt Proxy

The default configuration works out of the box for many use cases, but for authenticated encrypted DNS queries, you’ll want to customize the setup. The main configuration file is typically located at /etc/dnscrypt-proxy/dnscrypt-proxy.toml on installations via package managers, or dnscrypt-proxy.toml in the same directory as the binary for manual installations.

Selecting a Resolver

DNSCrypt Proxy ships with a curated list of public resolvers. You can find them in the public-resolvers.md file or within the configuration. For authenticated DNS, look for resolvers marked with [OK] and those supporting the dnscrypt protocol.

To use a specific resolver, edit your configuration file:

server_names = ['cloudflare', 'google', 'quad9']

For authenticated resolvers, you need to specify the resolver’s public key. Some popular authenticated options include:

dnscrypt.ca-1: Canadian resolver with authentication
cs-dns-us: US-based with DNSCrypt authentication

The configuration syntax for specifying a resolver with its fingerprint:

server_names = ['your-chosen-resolver']

Setting Up the Local Listener

Configure DNSCrypt Proxy to listen on a local address where your system or applications can send DNS queries:

listen_addresses = ['127.0.0.1:53']

This makes your local DNS server available at 127.0.0.1:53. You can use a different port if needed, for example 127.0.0.1:5353 to avoid conflicts with other services.

Enabling DNS Cache

DNSCrypt Proxy includes a built-in cache to reduce latency:

cache_size = 512
cache_min_ttl = 600
cache_max_ttl = 86400

The cache stores DNS responses locally, reducing round trips to the upstream resolver for frequently accessed domains.

Switching Your System to Use DNSCrypt

Once DNSCrypt Proxy is running, you need to direct your system’s DNS queries to it. The method depends on your Linux distribution and setup.

Method 1: Modify /etc/resolv.conf

The simplest approach is to point your system DNS to the local DNSCrypt Proxy:

sudo bash -c 'echo "nameserver 127.0.0.1" > /etc/resolv.conf'

For persistent configuration on systemd-resolved systems, you might need to create a symlink or modify the systemd configuration.

Method 2: Using systemd-resolved

If your system uses systemd-resolved, create a drop-in configuration:

sudo mkdir -p /etc/systemd/resolved.conf.d
sudo bash -c 'echo "[Resolve]" > /etc/systemd/resolved.conf.d/dnscrypt.conf'
echo "DNS=127.0.0.1" | sudo tee -a /etc/systemd/resolved.conf.d/dnscrypt.conf
sudo systemctl restart systemd-resolved

Method 3: NetworkManager Configuration

For NetworkManager-managed connections, you can set the DNS server directly:

sudo nmcli connection modify <connection-name> ipv4.dns "127.0.0.1"
sudo nmcli connection down <connection-name> && sudo nmcli connection up <connection-name>

Replace <connection-name> with your active network connection name (use nmcli connection to list them).

Starting and Enabling the Service

With systemd:

sudo systemctl enable dnscrypt-proxy
sudo systemctl start dnscrypt-proxy

Check the status:

sudo systemctl status dnscrypt-proxy

If you installed manually, you can run DNSCrypt Proxy directly:

sudo ./dnscrypt-proxy -config dnscrypt-proxy.toml

Verifying Your Setup

After configuration, verify that DNS queries are actually going through DNSCrypt.

Test with dig

Query your local DNSCrypt Proxy and check the response:

dig @127.0.0.1 example.com

If you get a valid response, DNSCrypt Proxy is processing queries.

Check Encrypted Traffic

Use tcpdump or Wireshark to confirm that DNS traffic leaving your machine is encrypted:

sudo tcpdump -i any -n port 53 or port 443

You should see minimal plain DNS traffic if DNSCrypt is working correctly.

Verify DNSCrypt Protocol

Some online tools can verify DNSCrypt functionality. The DNSCrypt resolver’s website provides testing methods, or you can query the DNS stamp of your resolver to confirm the protocol in use.

Advanced Configuration: Authentication

For maximum security, configure DNSCrypt Proxy to use resolvers that support client authentication. This requires obtaining or generating client credentials:

[client_auth]
# Authentication method: tls, http, dns, or none
auth_method = 'none'

# If your resolver requires authentication:
# auth_token = 'your-auth-token'

Some enterprise or privacy-focused resolvers require registration. Follow their documentation to obtain authentication credentials.

Troubleshooting Common Issues

DNS queries fail: Check that no other service is using port 53 (sudo lsof -i :53). Stop conflicting services or change DNSCrypt Proxy’s listening port.

Slow resolution: Enable the cache settings and consider using a resolver geographically closer to you.

Systemd-resolved conflicts: Ensure systemd-resolved isn’t also trying to handle DNS on the same port.

Logs: Check journalctl for DNSCrypt Proxy logs:

sudo journalctl -u dnscrypt-proxy -f

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