Protect Unassigned Numbers from Fraud

Identify and protect unassigned number inventory as Do Not Originate (DNO) to reduce spoofing, strengthen trust and support industry-wide fraud mitigation.

The Missing Signal in Robocall Prevention

Telephone numbers allocated to a service provider but not yet assigned to an end user can create an opportunity for misuse.

Bad actors can spoof these numbers to make fraudulent calls appear legitimate, potentially exposing consumers to fraud before a number ever reaches its intended end user.

Local Service providers need a reliable way to identify and protect unassigned number inventory that should not originate calls.

You can’t stop spoofing of unassigned numbers if networks don’t know which numbers should never originate calls.

Simple. Scalable. Trusted.

Helping service providers identify and protect unassigned number inventory while supporting a more trusted communications ecosystem.

Identify Unassigned Number Inventory

Identify unused and unassigned telephone numbers that should not originate calls.

Contribute DNO Data

Submit unassigned number inventory through RealNumber’s trusted framework and designate those numbers as DNO until they are assigned.

Enable Smarter Blocking

Give downstream providers, analytics platforms and enterprises actionable DNO intelligence to help identify calls originating from numbers that should not be in use.

Introduce Greater Trust with RealNumber® DNO Inventory

RealNumber® Do Not Originate (DNO) enables Resp Orgs, Service Provider ID (SPID) owners and Operating Company Number (OCNs) to proactively identify numbers as DNO, helping the ecosystem recognize and block unauthorized traffic before it reaches consumers.

By contributing DNO inventory data, you help create a stronger foundation for:

Robocall mitigation and fraud prevention
Reduced spoofing of inactive or unused numbers
Improved network integrity and trust
More accurate analytics and call treatment decisions
Industry-wide collaboration against fraudulent traffic

Introduce Greater Trust with RealNumber® DNO Inventory

Built for a More Trusted Calling Ecosystem

Trusted Contributor Framework

Establish a trusted framework for identifying and validating DNO inventory contributed by authorized industry participants, improving confidence in shared data while supporting more accurate fraud prevention and call authentication efforts.

Scalable Participation

Designed for SPID and OCN holders managing large numbering inventories, enabling organizations to designate unassigned numbers as DNO and protect them from spoofing and misuse until they are assigned to an end user.

Actionable Intelligence

Deliver trusted number intelligence that supports call blocking, analytics, fraud detection and operational workflows, helping service providers make more informed decisions and strengthen protections across the communications ecosystem.

Ecosystem Collaboration

Foster industry-wide collaboration by enabling trusted organizations to share DNO inventory information, strengthening collective efforts to combat spoofing, illegal robocalls and other communications fraud targeting consumers and businesses.

Trusted Framework Participation Intelligence Collaboration

Help Stop Brand Impersonation at the Source

RealNumber DNO helps service providers proactively identify numbers that should never originate calls — creating stronger signals for fraud prevention and trusted communications.

To learn more, schedule a demo today!

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