I've been conducting a comprehensive evaluation of Cloudflare One's Zero Trust Network Access (ZTNA) platform for the last quarter, focusing on its application as a replacement for traditional VPNs in a microservices architecture. My testing methodology involved deploying it across three distinct environments: a development Kubernetes cluster, a staging environment with legacy on-premise systems, and a production AWS VPC. The performance and security benchmarks are forthcoming in a separate thread, but one foundational configuration decision has prompted this immediate discussion.
Upon initial deployment of the Cloudflare WARP connector and configuration of the Zero Trust dashboard, I observed a significant discrepancy between the advertised "zero trust" model and the default outbound traffic behavior. The platform's default posture, after defining your first application or network resource, is to permit all outbound traffic from enrolled devices to the public internet. This is governed by the implicit `allow` rule that exists before any user-defined policies. For a product suite built on the principle of "never trust, always verify," this permissive default is logically inconsistent and introduces a measurable attack surface.
Consider the following typical initial policy setup for a simple web application:
```json
// Example of a basic application policy in dashboard
{
"action": "allow",
"principals": ["group:engineering"],
"resources": ["https://internal-app.corp.com"]
}
```
While this correctly restricts *access to* the internal application, it does nothing to control what the enrolled device (the "principal") can connect *out to*. The device can still initiate connections to any external IP or domain. The zero trust model should, in principle, extend to egress traffic as well, treating outbound connections as equally risky vectors for data exfiltration, malware command & control, or lateral movement.
To enforce a true least-privilege egress model, you must manually construct a default-deny outbound policy. This requires:
* Creating a "Block" rule for all destinations (`*`) as the first policy.
* Then, creating subsequent "Allow" rules for specific, required external services (e.g., `*.github.com`, `*.pkg.dev`, `apt.ubuntu.com`).
* Meticulously auditing all dependencies, which is non-trivial in modern development toolchains.
The operational overhead of maintaining this allow-list for outbound traffic is substantial, and the fact that it's not the default—or at least a prominent, guided configuration step during onboarding—undermines the core security proposition. I am interested in the community's experience on this point:
* Have you implemented strict outbound controls in your Cloudflare One deployment? What was the impact on developer experience or operational workflows?
* Are there documented best practices from Cloudflare that address this, or is the implicit allow considered an acceptable trade-off for usability?
* How does this default compare to other ZTNA/SASE platforms you've evaluated (e.g., Zscaler Private Access, Netskope)?
The security efficacy of any zero trust architecture is contingent on its default-deny configuration. Starting from an allow-all stance seems to contradict that foundational axiom.
-ck
You've hit on the operational reality that most zero trust vendors face: balancing security doctrine with user adoption friction. That default allow is less a philosophical stance and more a pragmatic deployment scaffold. It ensures initial connectivity for agent registration, DNS resolution, and certificate fetching before policies are fully baked.
From an integration standpoint, this is why I always treat the initial configuration as a transient state. My first step after deploying any ZTNA connector, be it Cloudflare's or another, is to build that explicit deny rule for outbound traffic, then carve out exceptions only for the necessary SaaS APIs and update services the agents require. It's tedious but turns that implicit allow into an explicit, auditable policy set.
connected