Securing Your Windows Server 2019 Network with DNS over HTTPS (DoH)

DNS over HTTPS (DoH) is an increasingly important security feature that encrypts DNS queries, protecting your network traffic from eavesdropping and manipulation. While Windows Server 2019 doesn't natively support DoH as a client, there are several ways to implement and benefit from it for enhanced security on your network.

Understanding the Benefits of DoH

Implementing DoH on your Windows Server 2019 network offers several significant advantages:

• Enhanced Privacy: DoH encrypts your DNS queries, preventing third parties (including your ISP) from seeing which websites you are accessing. This protects your browsing history and prevents potential tracking.
• Improved Security: Encryption safeguards against DNS spoofing and cache poisoning attacks, ensuring you connect to the legitimate websites intended. This protects against malicious redirects and phishing attempts.
• Resistance to Censorship: DoH makes it more difficult for entities to censor or block access to specific websites by intercepting DNS requests.

Implementing DoH on Windows Server 2019: Client-Side Approach

Since Windows Server 2019 itself doesn't directly support DoH as a client, the most practical approach involves configuring DoH on the individual client machines (workstations) that connect to your server. This requires modifying the DNS settings on each client machine.

Here's how you can configure DoH on a Windows client:

1. Choose a DoH Resolver: Select a reputable public DoH resolver such as Cloudflare (1.1.1.1), Google Public DNS (8.8.8.8), or Quad9 (9.9.9.9). Each has its own privacy policy, so review them carefully to choose the best option for your needs.
2. Modify DNS Settings: Open Network Connections, find your active network adapter, and click 'Properties'. Select 'Internet Protocol Version 4 (TCP/IPv4)' or 'Internet Protocol Version 6 (TCP/IPv6)', then click 'Properties'. Instead of using a traditional DNS server address, use the DoH resolver's address. However, this alone won't enable DoH. You'll need to use a third-party application or modify your browser settings to explicitly enable DoH.
3. Browser Configuration (Recommended): Modern browsers like Chrome, Firefox, and Edge offer built-in support for DoH. Check the browser's settings to enable DoH and specify your chosen resolver. This method ensures DoH is used consistently even if other applications don't support it.

Implementing DoH with a Forwarding DNS Server

For greater control and centralized management, you can set up a forwarding DNS server that supports DoH and route all DNS queries through it. This approach requires installing a DNS server software (like BIND or unbound) which are capable of acting as a DoH client and forwarding the resolved addresses to your Windows Server 2019 network. This method requires more technical expertise.

Steps to Configure a Forwarding DNS Server (example using unbound):

1. Install Unbound: Download and install Unbound on a Linux server (e.g., Ubuntu).
2. Configure Unbound: The configuration file (usually `unbound.conf`) needs to be edited to specify the upstream DoH server, the port, and possibly other parameters.
3. Configure Windows Server DNS: Configure your Windows Server 2019 DNS server to forward DNS queries to the Unbound server.

This setup necessitates understanding DNS server administration and Linux system management.

Security Considerations

While DoH enhances security, it's crucial to consider the following:

• Resolver Trust: Choosing a reputable DoH resolver is paramount. A compromised resolver could introduce vulnerabilities.
• Network Segmentation: Consider segmenting your network to isolate sensitive systems and minimize the impact of potential breaches.
• Monitoring and Logging: Implement robust monitoring and logging mechanisms to detect and respond to potential security incidents.

Conclusion

Implementing DoH on your Windows Server 2019 network requires a thoughtful approach. While not natively supported, the client-side approach or deploying a DoH-capable forwarding DNS server are viable options. The choice depends on your technical expertise and network architecture. By carefully planning and implementing DoH, you can significantly enhance the privacy and security of your network.