Zero Trust Network Access (ZTNA) might sound complex, but at its core, it’s about making sure only authorized users and devices can access your applications, regardless of their location. The traditional “castle-and-moat” security model, where everything inside the network is trusted, just doesn’t cut it anymore. With distributed workforces, cloud applications, and diverse device types, we need a more granular approach. This article will walk you through configuring a robust ZTNA solution using Tailscale and Cloudflare Tunnels, two powerful tools that simplify this often-daunting task.

Why Zero Trust?

In today’s interconnected world, simply being “inside” your network is no longer a guarantee of trust. Imagine an attacker gains access to a single internal device – with a traditional perimeter, they could potentially move laterally throughout your entire infrastructure.

Zero Trust flips this script, assuming nothing is trusted by default, even if it’s on your internal network.

Every access request, from any user or device, is explicitly verified. This drastically reduces the attack surface and enhances security.

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Understanding the Key Players

Before diving into the setup, let’s get acquainted with our primary tools:

Tailscale: Your Secure Mesh Network

Tailscale is a powerful mesh VPN that uses WireGuard to create a secure, encrypted network between all your devices, regardless of their location. Think of it as your own private internet, accessible only to your authorized devices.

Key Benefits of Tailscale

• Simplified VPN: Forget complex configurations. Tailscale handles NAT traversal, IP addressing, and key exchange automatically.
• Identity-Based Access: Authenticates users against your existing identity provider (Google, Microsoft 365, Okta, etc.), making user management a breeze.
• Least Privilege: Define granular access policies (ACLs) to control exactly which devices can talk to each other.
• Exit Nodes: Route all internet traffic from a device through a trusted node on your Tailscale network, enhancing privacy and security.
• Subnet Routers: Extend your Tailscale network to traditional subnets, allowing Tailscale-connected devices to access resources on those subnets without installing Tailscale on every device.

Cloudflare Tunnels: Exposing Internal Services Securely

Cloudflare Tunnels provide a secure way to expose your internal services to the internet without opening inbound firewall ports. Instead, a lightweight Cloudflare Daemon (cloudflared) runs inside your network, establishing an outbound-only connection to Cloudflare’s edge.

Key Benefits of Cloudflare Tunnels

• No Inbound Ports: Eliminates the need to open dangerous inbound ports on your firewall, significantly reducing your attack surface.
• Cloudflare’s Edge Security: Leverages Cloudflare’s massive global network for DDoS protection, WAF, and other security features.
• Identity-Aware Proxy (Access): Integrate with Cloudflare Access to add an extra layer of authentication and authorization before users can even reach your Tunnel.
• Easy Configuration: Setting up tunnels is relatively straightforward, often just a few commands.

Scenario: Securing an Internal Web Application

Let’s imagine you have a web application running on a server inside your private network. You want your team members to access it securely, from anywhere, without exposing it directly to the public internet. This is a perfect scenario for ZTNA with Tailscale and Cloudflare Tunnels.

Step-by-Step Configuration: Tailscale Setup

First, we’ll get Tailscale up and running on your server and client devices.

1. Sign Up and Install Tailscale

• Sign Up: Head over to Tailscale’s website and sign up using your preferred identity provider (Google, Microsoft, Okta, etc.). This will become your Tailscale administrator account.
• Install on Server: Install the Tailscale client on the server hosting your web application. For Linux, it’s usually a few simple commands:

“`bash

curl -fsSL https://tailscale.com/install.sh | sh

sudo tailscale up –authkey tskey-your-auth-key-here –hostname your-server-name

“`

You can generate an auth key in the Tailscale admin console for unattended installs.

• Install on Client Devices: Install Tailscale on the laptops, desktops, or mobile devices your team will use to access the application. Follow the instructions for your specific operating system on the Tailscale website.

2. Authorize Devices in Tailscale Admin Console

After installing, each device will appear in your Tailscale admin console (under “Machines”). You’ll need to authorize them to join your network. This is a one-time step for each device.

3. Configure Tailscale ACLs (Access Control Lists)

This is where the “Zero Trust” really comes into play. You’ll define who can access what.

• Edit ACLs: Go to your Tailscale admin console -> “Access Controls”.
• Basic ACL Example: Let’s say your web app is running on 10.0.0.100 within your Tailscale network (Tailscale assigns internal IPs, so this is just an example). You want members of your “developers” group to access it.

“`json

{

“acls”: [

// Allow all users in the “developers” group to connect to the web app server

{

“action”: “accept”,

“src”: [“group:developers”],

“dst”: [“tag:webserver:80”, “tag:webserver:443”] // Assuming you tag your web server

},

// Allow developers to SSH into the web app server

{

“action”: “accept”,

“src”: [“group:developers”],

“dst”: [“tag:webserver:22”]

}

],

“tagOwners”: {

“webserver”: [“group:admins”] // Only admins can apply the ‘webserver’ tag

},

“hosts”: {

“webserver”: “100.X.Y.Z” // Replace with the actual Tailscale IP of your web app server

}

}

“`

• Tags: Using tags (tag:webserver) is a good practice. You apply the tag to the server in the “Machines” section of your Tailscale admin console.
• Groups: Users are automatically grouped based on your identity provider. You can also define custom groups in Tailscale.
• Apply and Test: Save your ACLs. Now, only users in the “developers” group should be able to access the web app server via its Tailscale IP.

4. (Optional) Subnet Router

If your web application isn’t directly on the Tailscale-enabled server but on another server within the same private subnet, you can use a Tailscale Subnet Router.

• Enable IP Forwarding: On your Tailscale-enabled server (the one acting as the subnet router):

“`bash

sudo sysctl -w net.ipv4.ip_forward=1

sudo sysctl -w net.ipv6.conf.all.forwarding=1

“`

• Advertise Subnet: Tell Tailscale to advertise the subnet:

“`bash

sudo tailscale up –advertise-routes=192.168.1.0/24 –hostname your-router-name

“`

(Replace 192.168.1.0/24 with your actual subnet).

• Approve in Admin Console: In the Tailscale admin console -> “Machines”, approve the advertised route for your subnet router.
• Update ACLs: Adjust your ACLs to allow access to resources on that subnet.

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Step-by-Step Configuration: Cloudflare Tunnels Setup

Now, let’s set up the Cloudflare Tunnel to expose your internal application to a public (but protected) URL.

1. Set Up Cloudflare Account and Domain

• Sign Up: If you don’t have one, sign up for a Cloudflare account.
• Add Domain: Add your domain to Cloudflare (e.g., yourcompany.com). Follow the instructions to change your domain’s nameservers to Cloudflare’s.
• Create Subdomain: Decide on a subdomain for your internal app (e.g., app.yourcompany.com).

2. Install Cloudflared Daemon

• Install on Server: Install the cloudflared daemon on the same server where your web application is running (or a server that can reach your web app).

“`bash

For Debian/Ubuntu

curl -L –output cloudflared.deb https://github.com/cloudflare/cloudflared/releases/latest/download/cloudflared-linux-amd64.deb

sudo dpkg -i cloudflared.deb

For other OS, check Cloudflare’s documentation:

https://developers.cloudflare.com/cloudflare-one/connections/connect-apps/install-and-setup/installation

“`

3. Authenticate Cloudflared

• Authenticate: Run the authentication command. This will open a browser window for you to log in to your Cloudflare account and authorize cloudflared.

“`bash

cloudflared tunnel login

“`

This creates a certificate file (.cloudflared/cert.pem) on your server.

4. Create and Configure a Cloudflare Tunnel

• Create Tunnel:

“`bash

cloudflared tunnel create my-web-app-tunnel

“`

This will generate a Tunnel ID. Make a note of it.

• Create Configuration File: Create a config.yml file in your .cloudflared directory.

“`yaml

~/.cloudflared/config.yml

tunnel:

credentials-file: /root/.cloudflared/.json # Or wherever your creds file is

ingress:

• hostname: app.yourcompany.com

service: http://localhost:8080 # Or the IP and port of your actual web app

• service: http_status:404 # Catch-all for anything else

“`

• Replace with the ID generated earlier.
• Adjust service to point to your web application’s internal IP and port. If it’s on the same server, localhost is fine.
• The credentials-file path might vary depending on your OS and user.
• Run Tunnel (Test):

“`bash

cloudflared tunnel run my-web-app-tunnel

“`

This will start the tunnel. You should see it connecting to Cloudflare’s edge.

• Create DNS Record: While the tunnel is running, go to your Cloudflare DNS settings. Create a CNAME record:
• Type: CNAME
• Name: app (or your chosen subdomain)
• Target: .cfargotunnel.com
• Proxy Status: Proxied (orange cloud)

This links your subdomain to your Cloudflare Tunnel.

5. Integrate Cloudflare Access for Identity-Aware Protection

This is crucial for ZTNA on the public-facing side. Cloudflare Access acts as an Identity-Aware Proxy.

• Go to Cloudflare Zero Trust Dashboard: Navigate to dash.cloudflare.com -> “Zero Trust” (on the left sidebar).
• Enable Cloudflare Access: If you haven’t already, enable Cloudflare Access for your domain.
• Create an Access Application:
• Go to “Access” -> “Applications”.
• Click “Add an application”.
• Choose “Self-hosted” (for your Cloudflare Tunnel).
• Application Name: My Internal Web App
• Subdomain: app.yourcompany.com (your chosen subdomain)
• Session Duration: Set an appropriate session timeout (e.g., 24 hours).
• Click “Next”.
• Configure Access Policies: This defines who can access your application.
• Policy Name: Allow Team Members
• Action: Allow
• Filter: Choose your identity provider (e.g., “Emails” -> “include” -> *@yourcompany.com or specific email addresses, or “Groups” if your IdP supports it).
• You can add multiple rules (e.g., “Require” a specific country, “Block” a certain IP range).
• Click “Add application”.
• Test Access: Try accessing app.yourcompany.com in your browser. You should be redirected to your identity provider’s login page. After successful authentication, you’ll be granted access to your internal web application.

6. (Optional) Run Cloudflared as a Service

To ensure your tunnel starts automatically and stays running, configure cloudflared as a system service.

• Install Service:

“`bash

sudo cloudflared tunnel service install

“`

• Start and Enable:

“`bash

sudo systemctl start cloudflared.service

sudo systemctl enable cloudflared.service

“`

• Check Status:

“`bash

sudo systemctl status cloudflared.service

“`

Combining Tailscale and Cloudflare Tunnels: The ZTNA Synergy

You now have two layers of Zero Trust protection:

1. Cloudflare Access: Protects the public entry point to your application. Only authenticated and authorized users (via your IdP) can even reach your Cloudflare Tunnel. This means even if an attacker knew your URL, they couldn’t bypass Cloudflare’s authentication.
2. Tailscale: Protects your internal network and provides secure access to other internal resources. While Cloudflare Tunnels expose one specific application, Tailscale gives your authorized users a secure, direct path to any resource on your internal network (that they are permitted to access via Tailscale ACLs).

When to use which?

• Cloudflare Tunnels + Access: Ideal for exposing specific web applications or APIs that need to be accessible from the public internet, but only to authenticated users. It hides your origin IP and leverages Cloudflare’s edge security.
• Tailscale: Best for giving your team secure, direct access to all internal resources (file shares, SSH, RDP, internal tools, databases) without exposing them to the internet at all. It’s also great for device-to-device connectivity.

Advanced Considerations and Best Practices

To make your ZTNA setup even more robust:

1. Identity Provider Integration

• Centralized Identity: Ensure both Tailscale and Cloudflare Access are integrated with the same identity provider (e.g., Google Workspace, Azure AD, Okta). This centralizes user management and authentication, making administration much easier and more secure.
• Multi-Factor Authentication (MFA): Enforce MFA on your identity provider. This adds a critical layer of security to prevent unauthorized access even if credentials are stolen.

2. Fine-Grained Access Policies

• Tailscale ACLs: Regularly review and refine your Tailscale ACLs. Follow the principle of least privilege – grant only the necessary access.
• User/Group Segmentation: Divide your users into logical groups (e.g., developers, marketing, finance) and create ACLs that reflect their specific access needs.
• Service Segmentation: Use tags for different types of services (e.g., tag:databases, tag:ssh-servers) to simplify ACL management.
• Cloudflare Access Policies: Leverage Cloudflare Access policies beyond just email addresses.
• Device Posture: Use Cloudflare WARP to check device health and compliance before granting access.
• Geographic Restrictions: Restrict access based on the user’s location if appropriate.
• IP Restrictions: Allow only specific IP ranges for certain sensitive applications.

3. Monitoring and Logging

• Audit Logs: Both Tailscale and Cloudflare provide detailed audit logs. Regularly review these logs for unusual activity, failed login attempts, or policy violations.
• Tailscale Logs: Check tailscaled logs on your devices and the Tailscale admin console.
• Cloudflare Logs: Access logs in the Cloudflare Zero Trust dashboard.
• SIEM Integration: Integrate logs from both platforms with a Security Information and Event Management (SIEM) system for centralized monitoring and alerting.

4. Device Posture and Health Checks

• Tailscale: Use Tailscale’s device attributes in ACLs to grant access only to devices that meet certain criteria (e.g., OS version, specific tags).
• Cloudflare Access with WARP: Cloudflare WARP client can be deployed on your team’s devices to enforce security policies and perform device posture checks (e.g., checking for antivirus status, disk encryption) before allowing access to applications behind Cloudflare Access.

5. Regular Audits and Reviews

• Periodic Reviews: Conduct regular audits of your user accounts, access policies, and device configurations. Remove stale accounts and outdated policies.
• Vulnerability Scans: Perform vulnerability scans on your internal applications and servers regularly. Even with ZTNA, patching and securing your underlying infrastructure is critical.

Conclusion

Implementing Zero Trust Network Access doesn’t have to be an overwhelming undertaking. By strategically combining Tailscale and Cloudflare Tunnels, you can create a powerful, multi-layered security architecture that protects your applications and data. Cloudflare Tunnels with Access secures your public-facing applications at the edge, while Tailscale provides a secure, private mesh network for all your internal resources. This synergy ensures that every access request is authenticated, authorized, and continuously verified, significantly bolstering your organization’s security posture in an increasingly distributed and cloud-centric world.

FAQs

What is Zero Trust Network Access (ZTNA)?

Zero Trust Network Access (ZTNA) is a security model that requires strict identity verification for every person and device trying to access resources on a private network, regardless of whether they are inside or outside the network perimeter.

What is Tailscale?

Tailscale is a zero config VPN built on a modern protocol that is secure, performant, and easy to use. It allows users to securely access their resources from anywhere, without the need for complex networking configurations.

What are Cloudflare Tunnels?

Cloudflare Tunnels allow users to securely connect their infrastructure to Cloudflare’s network without exposing it to the public internet. This provides a secure and fast way to connect resources to Cloudflare’s global network.

How can Tailscale and Cloudflare Tunnels be configured for Zero Trust Network Access?

Tailscale and Cloudflare Tunnels can be configured together to create a secure and private network that follows the principles of Zero Trust Network Access. By using Tailscale for secure VPN connections and Cloudflare Tunnels for secure access to resources, organizations can ensure that only authorized users and devices can access their network.

What are the benefits of using Tailscale and Cloudflare Tunnels for Zero Trust Network Access?

By using Tailscale and Cloudflare Tunnels for Zero Trust Network Access, organizations can benefit from secure and private connections, simplified network configurations, and the ability to easily manage and control access to resources from anywhere. This approach also provides a high level of security and performance for accessing resources on the network.