# Do-Not-Originate (DNO) List Enforcement Guide

## Implementation Handbook for Voice Service Providers

**Prepared by Performance West Inc.**
**Effective Date: 2026**

---

## 1. What Is the DNO List?

The FCC Do-Not-Originate (DNO) list is a database of telephone numbers that should **never** appear as the calling party number on the public switched telephone network (PSTN). These numbers are known to be used for illegal robocalling, spoofing, or fraud.

The DNO list is maintained by the **Industry Traceback Group (ITG)**, operated by USTelecom — the Broadband Association, and is distributed to voice service providers and gateway providers for enforcement.

**Regulatory basis:** 47 CFR § 64.6305 (2025 RMD Report & Order, effective February 5, 2026)

---

## 2. Who Must Enforce the DNO List?

All providers who file in the FCC Robocall Mitigation Database:
- **Voice Service Providers** (originating carriers)
- **Gateway Providers** (receiving international traffic)
- **Intermediate Providers** (transit/tandem carriers)

If you have an RMD filing, you are expected to enforce the DNO list.

---

## 3. Implementation Steps

### Step 1: Obtain the DNO List

**Check with your switch/platform provider first.** Many VoIP platforms, hosted PBX providers, and wholesale carriers already include DNO list enforcement as part of their service at no extra cost. If your provider handles this for you, confirm it in writing and reference it in your RMD filing — you may not need to manage the list yourself.

**If your platform does NOT include DNO enforcement,** you must obtain the DNO registry directly:

- **DNO Registry:** https://tracebacks.org/dno-registry/
- This is the official source operated by USTelecom's Industry Traceback Group (ITG)
- The registry provides a downloadable list of numbers that must be blocked
- Register for access and download the current list
- Updates are published regularly — check the registry for the current update schedule

**Other sources that may include DNO enforcement:**
- Call analytics vendors (TransNexus, Neustar, Hiya) often include DNO blocking in their platforms
- Your upstream carrier may already block DNO-listed numbers before they reach your network

### Step 2: Integrate into Your Call Routing

**For SIP/VoIP infrastructure:**

```
# Example: SIP proxy rule (Kamailio/OpenSIPS/FreeSWITCH concept)
# Block calls where the FROM or P-Asserted-Identity matches a DNO number

if (is_in_dno_list($fU)) {
    sl_send_reply("603", "Decline - DNO Listed Number");
    exit;
}
```

**Implementation options by platform:**

| Platform | Method |
|---|---|
| FreeSWITCH | Load DNO list into mod_blacklist or use a Lua/Python script in dialplan |
| Kamailio | Hash table lookup in route block, loaded from DB or file |
| Asterisk | Use a database-backed dialplan function (ODBC or AstDB) |
| Metaswitch | Policy rule in call control configuration |
| BroadSoft/Cisco BroadWorks | System-level origination blocking rule |
| Cloud UCaaS | Contact your UCaaS vendor — they should enforce DNO on your behalf |

### Step 3: Apply to All Call Origination Points

The DNO check must be applied at **every point where calls enter your network**:

1. **Customer-facing SIP trunks** — check the calling number before routing
2. **Gateway interfaces** — check foreign-originated traffic at ingress
3. **Wholesale interconnections** — check traffic received from downstream carriers
4. **SIP registration** — optionally prevent registration of DNO-listed numbers as extensions

### Step 4: Establish an Update Schedule

| Frequency | Action |
|---|---|
| **Daily** (recommended) | Download latest DNO list, update blocking rules |
| **Immediately** | If you receive a traceback request identifying a DNO number you're originating, block within 4 hours |
| **Monthly** | Audit your blocking logs to confirm DNO enforcement is working |

### Step 5: Log and Report

Maintain logs of:
- DNO list version/date loaded
- Number of calls blocked per day due to DNO match
- Any exceptions or overrides (there should be none for DNO numbers)
- Date and time of each list update

These logs demonstrate compliance if the FCC or ITG requests evidence of enforcement.

---

## 4. What to Do If a Customer Complains

If a legitimate customer reports their number is being blocked:

1. Verify the number against the current DNO list
2. If the number IS on the DNO list, the customer must contact the ITG to request removal
3. Do NOT create exceptions to bypass DNO blocking — this violates your RMD certification
4. Document the complaint and your response

---

## 5. Documenting DNO Enforcement in Your RMD Filing

Your RMD certification and/or robocall mitigation plan (Exhibit A) should include language such as:

> "[Company Name] immediately blocks any numbers identified on the FCC Do-Not-Originate (DNO) list. DNO list updates are applied daily to prevent origination of calls from numbers known to be used for illegal robocalling. Blocking is enforced at all network ingress points including customer SIP trunks, gateway interfaces, and wholesale interconnections."

---

## 6. Common Mistakes to Avoid

| Mistake | Consequence |
|---|---|
| Not mentioning DNO in your RMD filing | Filing flagged as deficient |
| Updating the list monthly instead of daily | Stale data allows blocked numbers through |
| Only blocking on one trunk, not all ingress | Partial enforcement = non-compliance |
| Creating manual exceptions for "known good" customers | Undermines the entire program |
| Not logging blocked calls | Cannot demonstrate compliance to FCC/ITG |

---

## 7. Resources

- **Industry Traceback Group:** https://tracebacks.org
- **USTelecom:** https://www.ustelecom.org
- **FCC RMD Portal:** https://apps.fcc.gov/rmd/
- **47 CFR § 64.6305:** https://www.ecfr.gov/current/title-47/chapter-I/subchapter-B/part-64/subpart-CC
- **2025 RMD Report & Order:** FCC 25-6 (effective February 5, 2026)

---

*This guide is provided for informational purposes as part of your RMD filing service. It is not legal advice. Consult with your regulatory counsel for implementation decisions specific to your network.*

*Performance West Inc. — performancewest.net — 1-888-411-0383*
