Configuring DNS over HTTPS (DoH) on Windows Server 2016: A Comprehensive Guide

Windows Server 2016 doesn't natively support DNS over HTTPS (DoH). Unlike newer operating systems, it lacks built-in functionality to leverage this privacy-enhancing DNS protocol. However, achieving DoH functionality on Windows Server 2016 is still possible, albeit requiring a different approach than simply flipping a switch. This guide will explore several methods, their pros and cons, and provide detailed instructions.

Understanding DNS over HTTPS (DoH)

DNS over HTTPS encrypts DNS queries and responses, preventing eavesdropping and manipulation of DNS traffic. This enhances privacy and security, particularly on public Wi-Fi networks. Instead of using the standard UDP or TCP port 53, DoH uses HTTPS over port 443, leveraging the existing infrastructure of secure web communication.

Methods for Implementing DoH on Windows Server 2016

There are primarily two strategies for enabling DoH on a Windows Server 2016 environment:

1. Using a Client-Side DoH Resolver: This involves configuring individual client machines (e.g., workstations, laptops) to use a DoH-compatible DNS resolver. This is the simplest approach but doesn't provide server-side DoH enforcement.
2. Deploying a Proxy Server with DoH Capabilities: This requires setting up a proxy server (like Squid or a similar solution) configured to use DoH. All client machines would then route their DNS requests through this proxy, effectively enforcing DoH for the entire network. This provides more centralized control and policy enforcement.

Method 1: Client-Side DoH Configuration

This method is suitable for smaller networks or situations where centralized DoH management isn't a requirement. Most modern browsers (Chrome, Firefox, Edge) support configuring DoH directly within their settings. For other applications, you'll need to change the DNS server settings in the network adapter properties to a public DoH resolver's address, such as Cloudflare (1.1.1.1 or 1dot1dot1dot1.cloudflare-dns.com) or Google Public DNS (8.8.8.8).

Steps (example using Cloudflare):

1. Open Network Connections.
2. Select the network adapter.
3. Properties -> Internet Protocol Version 4 (TCP/IPv4) -> Properties.
4. Select 'Use the following DNS server addresses'.
5. Enter 1.1.1.1 as the Preferred DNS server and 1.0.0.1 as the Alternate DNS server.
6. Click OK to save the changes.

Note: This doesn't truly utilize DoH but rather routes the DNS requests to a server that supports it. The connection between the client and the DoH server will be encrypted, but the server itself may still log data. It is still a privacy improvement compared to unencrypted DNS.

Method 2: Deploying a DoH-Capable Proxy Server (More Complex)

This method offers better control and security but requires more technical expertise. You'll need to install and configure a proxy server (e.g., Squid) and then configure clients to route their DNS traffic through it. Squid itself may need additional configuration or extensions to support DoH. This often involves using a custom configuration file and potentially additional software like `dnsmasq` for local name resolution. There are various tutorials and guides available online for configuring Squid and other proxies with DoH support.

Conclusion

While Windows Server 2016 doesn't natively support DoH, you can still achieve similar privacy benefits through careful configuration. The client-side approach is simpler to implement but lacks centralized management. The proxy server method offers more control but requires greater technical expertise. Choose the method that best suits your technical capabilities and network requirements. Always prioritize using a trustworthy DoH provider and keep your systems updated.