Insights

After December 15: How to Strengthen Your “Reasonable DNO List” Compliance Posture

Dec 16, 2025

The Federal Communications Commission’s (FCC) December 15, 2025 effective date has passed, so carriers and voice service providers should confirm their outbound call blocking is operating now using a reasonable Do Not Originate (DNO) list and that the program is defensible. This is a moment for action, not alarm. DNO blocking is no longer a theoretical best practice, and a list that is too narrow, outdated or hard to justify creates avoidable risk.

In practice, “reasonable” comes down to a few operational fundamentals: lists may cover invalid, unallocated, unused and subscriber-requested block numbers. Lists that omit obvious categories will be deemed unreasonable.

RealNumber® DNO is designed for exactly this moment. It helps carriers and service providers implement and maintain a DNO program that is not only operational, but also reasonable and defensible.

With RealNumber® DNO, providers can:

• Use a comprehensive DNO list built to support compliance expectations

• Rely on trusted sourcing and continuous updates to reduce list drift and operational burden

• Incorporate the Industry Traceback Group (ITG) Number Set, which includes numbers vetted and identified as being spoofed to facilitate illegal, fraudulent or malicious traffic

• Implement efficiently via API integration, supporting consistent enforcement across outbound call flows

The result is a stronger compliance posture, reduced fraud exposure and a clearer story to tell internally and externally about how you are protecting consumers and network integrity.

What to do next: a practical 3-step checkpoint

If you are reviewing your posture after December 15, here are three actions that move the needle quickly:

1. Validate your DNO coverage against the categories your program should be blocking

2. Confirm your update cadence and ownership so the list stays current and accountable

3. Verify consistent enforcement across outbound call paths and document it in plain language

Take action now, with confidence

The most effective response to a post-effective-date environment is not to wait. It is to strengthen your controls now with a reasonable DNO list and a process you can stand behind.

If you want a fast, practical path forward, contact Somos to schedule a DNO readiness review and see how RealNumber® DNO can support compliance, reduce risk and protect your customers.

Request a RealNumber® DNO demo or schedule a DNO readiness review with Somos at connect@somos.com