Microsoft Azure IP ranges & what they mean for fraud

Microsoft Azure publishes the most granular range set of any cloud — tens of thousands of per-service prefixes.

How Maskbreak uses these ranges

Maskbreak tags traffic from these ranges with the dch (datacenter/hosting) signal in real time. The numbers above come from Microsoft Azure's own published range feed — the same feed Maskbreak's verdict pipeline refreshes daily, so a new range is scored within a day of publication, not whenever a static database ships.

Range data adds a signal; it never overrides deeper network detection. VPN exits live in datacenters, so a range hit doesn't short-circuit tunnel analysis — an IP in Microsoft Azure's ranges that is also a VPN exit gets both signals, and your policy sees the full picture in the reasons array.

What these ranges actually cover

Microsoft publishes the most granular range set of any cloud — tens of thousands of prefixes tagged by service and region, spanning virtual machines, Functions, App Service, and the Microsoft 365 service endpoints.

The granularity is a double-edged asset. It lets you separate rented compute from Microsoft's own SaaS egress, which is essential: traffic from Microsoft 365 prefixes is often a genuine corporate user or an Office integration, not an attacker. Treating the whole Azure footprint as one undifferentiated block is how you end up flagging enterprise customers.

Where this provider shows up in abuse

Azure's file is published weekly behind a confirmation page, which makes it the flakiest of the nine feeds to automate. Maskbreak treats a stale fetch as "keep the previous data" rather than losing coverage.

None of this makes a range match a verdict. In Maskbreak's pipeline a datacenter hit contributes 40 points toward a 0–100 risk score — enough to reach review, never enough to block on its own — and it never short-circuits tunnel detection, because VPN and proxy exits are themselves hosted in datacenters. Which AS announces a given address is a separate question, answered in the ASN directory.

Should you block Microsoft Azure traffic?

Azure VMs and Functions appear in bot traffic for the same reason AWS does: minute-billed compute with a clean corporate ASN. Legitimate enterprise integrations also live here in volume.

The honest answer is: it depends on the surface. A datacenter IP on a signup, login, or checkout is a strong review signal — humans overwhelmingly arrive from residential and mobile networks. The same IP calling your API is often just a legitimate backend. Maskbreak returns the raw signal so you can apply exactly that asymmetric policy instead of a blanket block.

curl -X POST https://maskbreak.com/v1/evaluate \
  -H "Authorization: Bearer sk_test_sandbox" \
  -H "Content-Type: application/json" \
  -d '{"token":"test_datacenter"}'

The sandbox key returns the documented datacenter-verdict shape (decision, risk_score, network.datacenter) — no signup required. Details in the API docs.