Comparing AdGuard Home Setups: Cloudflare Zero Trust vs. Tailscale in a Home Lab Environment

Introduction

Running a home lab offers immense flexibility and control over your network services. When it comes to setting up a customized DNS service with AdGuard Home, choosing the right method to expose and secure your DNS and management interfaces is crucial. Two popular approaches include using Cloudflare Zero Trust with Cloudflared and leveraging Tailscale to create a virtual private network (VPN). This article will delve into these two setups, comparing their advantages and disadvantages, and provide recommendations based on specific use cases.

Option 1: Using Cloudflared with Cloudflare Zero Trust

Overview

The first approach involves using Cloudflared, a tool that establishes secure tunnels between your local instance and the Cloudflare network. By integrating with Cloudflare Zero Trust, you can expose your AdGuard Home instance over DNS over HTTPS (DoH), allowing secure DNS queries over HTTPS.

Advantages

1. Global Accessibility: By exposing the DNS service over DoH through Cloudflare, you make it accessible from anywhere without the need for a VPN connection.
2. Performance: Cloudflare's vast global network can potentially offer low-latency connections due to their distributed edge servers.
3. Ease of Use: Setting up Cloudflared with Cloudflare Zero Trust can be straightforward, especially if you're already using Cloudflare for DNS or other services.
4. Bypassing VPN Limitations: On devices where VPN usage is limited (e.g., Android devices where you're already using a VPN for AdGuard), this method doesn't require an additional VPN connection.

Disadvantages

1. Security Concerns: Exposing the /dns-query endpoint to the public internet can be a security risk, as it might be susceptible to attacks if not properly secured.
2. Limited Protocol Support: DNS over TLS (DoT) may not be available in this setup, limiting you to DoH only.
3. Complex Access Control: While you can secure the management interface through Cloudflare Zero Trust policies, securing the DNS service itself might be more challenging.
4. Potential Compliance Issues: Sending DNS queries through Cloudflare might raise privacy concerns, depending on your compliance requirements.

Option 2: Exposing AdGuard Home via Tailscale

Overview

The second approach uses Tailscale, a mesh VPN network based on WireGuard, to expose your AdGuard Home instance's ports (typically 443 for HTTPS and 853 for DoT) to devices within your private network.

Advantages

1. Enhanced Security: By keeping the DNS service within a VPN, you reduce exposure to the public internet, mitigating potential security risks.
2. Full Protocol Support: You can utilize both DoT and DoH protocols, providing flexibility for different client configurations.
3. Simplified Access Control: Since only devices connected to your Tailscale network can access the services, you inherently restrict access to trusted devices.
4. Privacy Preservation: Your DNS queries stay within your private network, not passing through third-party servers.

Disadvantages

1. Continuous VPN Connection Required: Devices need to maintain a 24/7 connection to the Tailscale network, which may not be practical for all scenarios.
2. VPN Limitations on Devices: On Android devices, you cannot run multiple VPNs simultaneously. If you're using AdGuard's local VPN feature for ad-blocking and HTTPS interception, adding Tailscale isn't feasible.
3. Dependency on Tailscale: Relying on a third-party VPN service introduces another point of failure and potentially adds latency.
4. Potential Battery Drain: Maintaining a constant VPN connection can consume additional battery power on mobile devices.

Challenges with Android Devices

A significant consideration in this comparison is the limitation on Android devices regarding simultaneous VPN connections. Since AdGuard uses a local VPN to filter ads and perform HTTPS interception, adding Tailscale's VPN isn't possible. This limitation impacts the practicality of Option 2 for users heavily reliant on Android devices with AdGuard active.

Alternative Solutions

Given the limitations of both options, especially concerning Android devices, here are some alternative approaches:

1. Self-Hosted VPN Solutions:

   • WireGuard VPN: Set up your WireGuard VPN server on your home lab. This gives you full control over the VPN infrastructure without relying on third-party services like Tailscale.
   • Pros: You can customize configurations, support multiple protocols, and maintain privacy.
   • Cons: Requires additional setup and maintenance effort.

2. Hybrid Approach with Split Tunneling:

   • Configure Tailscale or another VPN with split tunneling to route only DNS traffic through the VPN while other traffic goes through the regular network.
   • Pros: Reduces bandwidth usage over VPN and might help with VPN limitations.
   • Cons: Complex to set up and might not resolve the Android VPN limitation.

3. Use of DNSCrypt or DNS over QUIC:

   • Implement DNSCrypt or DNS over QUIC to secure DNS queries without requiring a VPN connection.
   • Pros: Provides encrypted DNS without additional VPN overhead.
   • Cons: May not be supported by all clients and requires additional configuration.

4. Deploying a Public DoH/DoT Server with Strong Authentication:

   • Expose your AdGuard Home with DoH/DoT to the public internet but implement client authentication, such as mutual TLS, to secure access.
   • Pros: Accessible without VPN, and improves security over Option 1.
   • Cons: More complex SSL/TLS setup and certificate management.

5. Leverage AdGuard Public DNS Servers:

   • Use AdGuard's public DNS servers for DNS resolution while maintaining your local ad-blocking.
   • Pros: Simplifies setup and reduces maintenance.
   • Cons: Less control over DNS filtering policies and potential privacy concerns.

Recommendation

Considering the constraints, especially with Android devices and the need for continuous ad-blocking via AdGuard's local VPN, Option 1 (using Cloudflared with Cloudflare Zero Trust) appears more practical. However, to address the security concerns of exposing the /dns-query endpoint to the public internet, the following measures are recommended:

1. Implement Access Control Policies:

   • Use Cloudflare Zero Trust policies to restrict access to the DNS endpoint. Configure authentication measures like mutual TLS or JWT tokens if supported.

2. Regularly Update and Monitor:

   • Keep your AdGuard Home and Cloudflared instances updated to protect against vulnerabilities.
   • Monitor access logs for any suspicious activities.

3. Limit Exposure:

   • If possible, restrict the DNS service to specific IP addresses or ranges that you commonly use.

4. Alternative Ports and Obfuscation:

   • Run the DNS service on non-standard ports to reduce the likelihood of automated attacks.

While Option 2 provides better security by keeping everything within a VPN, the practical limitations on Android devices make it less feasible if you require AdGuard's local VPN functionality for ad-blocking and HTTPS interception.

Conclusion

Choosing between Cloudflare Zero Trust with Cloudflared and Tailscale for exposing your AdGuard Home instance depends on your specific needs and the devices you primarily use. For users heavily reliant on Android devices with AdGuard's VPN features, Option 1 offers a more compatible solution, provided that additional security measures are implemented to protect the exposed DNS service.

However, if device compatibility isn't an issue and maximum security is desired, leveraging a VPN like Tailscale or setting up your WireGuard server might be preferable. Always weigh the trade-offs between accessibility, security, and practicality when configuring services in your home lab.

Final Thoughts

Home labs are excellent for learning and customizing your network environment. Ensure that whichever method you choose, you remain vigilant about security practices. Regular updates, strong authentication, and careful exposure of services will help keep your network secure while providing the functionality you need.