Insights

Strengthening the Fight Against Illegal Robocalls: FCC Sets December 15, 2025 Effective Date

Sep 17, 2025

On Tuesday, September 16, the Federal Communications Commission (FCC) set a firm effective date of December 15, 2025 for key obligations under its Advanced Methods To Target and Eliminate Unlawful Robocalls rule (federalregister.gov).

All service providers must take decisive action now. Using a reasonable Do Not Originate (DNO) list will be central to meeting the new requirements. Using a reasonable Do Not Originate (DNO) list will be central to meeting the new requirements. Somos’ RealNumber® DNO product is built precisely for this moment.

What Service Providers Must Know Before December 15

The FCC’s new rule requires every provider in the call path to:

• Block calls using a reasonable DNO list 
  Lists may cover invalid, unallocated, unused and subscriber-requested block numbers. Lists that omit obvious categories will be deemed unreasonable.

• No notification required for DNO
  Providers blocking calls using a DNO list have no notification requirement, whereas providers that block calls using analytics must return the SIP “603+” code to alert the caller. Blocking using a broad DNO list will significantly cut down on required notifications, saving time and resources.

• Limit enforcement exposure 
  Failure to meet these obligations can result in traffic blocking and enforcement penalties. This is both a compliance challenge and an opportunity to strengthen consumer trust by reducing fraud at the network level.

How Somos’ RealNumber® DNO Helps Providers Comply

Somos has long anticipated these requirements. RealNumber® DNO is already delivering the scale, accuracy and agility service providers need with:

• Over 6 billion non-originating numbers flagged, covering Toll-Free, local, invalid, unallocated and subscriber-requested block numbers. 

• The Industry Traceback Group (ITG) Number Set that have been thoroughly vetted and identified as numbers spoofed to facilitate illegal, fraudulent or otherwise malicious traffic.

• Easy API Integration: Available via API for simple and efficient implementation to ensure you have the most up-to-date information possible.

• Continuously updated lists from trusted administrators like NANPA and, the TFN Registry™.

With RealNumber® DNO, service providers can ensure their DNO list is not only “reasonable” but also comprehensive, accurate and defensible.

The Path Forward

The countdown to December 15, 2025 has begun. Providers must act now to implement strong mitigation strategies, ensure their DNO lists are compliant, and be ready for analytics-based call blocking and notification rules.

Contact Somos today to put RealNumber® DNO to work for your network. Protect your customers, reduce risk and stay ahead of evolving FCC requirements.

Read the full FCC order here: Federal Register – Advanced Methods To Target and Eliminate Unlawful Robocalls