VoIP Caller: What It Means and How to Identify, Block or Report One

By The Uptime Report Team · Last reviewed: October 2026

A “VoIP Caller” label usually means an internet-based number called and no caller name reached your phone. It is not a scam signal by itself: let it go to voicemail and call back only on a number you trust.

What is a VoIP caller?

A VoIP caller is any person or system placing a call through a Voice over Internet Protocol service instead of a switched copper line. Under 47 CFR 9.3, interconnected VoIP needs a broadband connection and IP-compatible equipment and can call to and from the public telephone network. For US business lines, that is now the normal case.

FCC Form 477 data in our VoIP statistics report show that 83.6% of US business and government wireline voice connections were VoIP in June 2025: 44.0 million, against 8.6 million switched lines. Of those, 26.4 million were over-the-top VoIP on separately bought broadband, the model behind most hosted VoIP phone systems. Your bank, suppliers and clients mostly call from VoIP numbers, so the useful test is whether the number shown is authentic.

Why does caller ID say “VoIP Caller”?

Caller ID usually shows “VoIP Caller” or a similar generic label when no specific caller name reaches your phone for the number; no FCC rule defines that label. Microsoft’s Teams documentation (Microsoft Learn, September 2026) puts caller name display on the terminating carrier and notes that US names go stale when carriers delay refreshing the authoritative CNAM databases. The label alone says nothing about intent.

Warning labels are a separate layer, added by whoever handles the call last. Verizon’s feedback form lists its labels as Potential Spam, Potential Fraud, Robo caller and SPAM?, and says a call showing another label, such as SPAM LIKELY, was not labeled by Verizon. T-Mobile separates Scam Likely, for likely fraud, from Potential Spam, for unwanted solicitation, and Microsoft Teams can rewrite caller ID to “Spam likely” itself.

The digits do not reveal the technology either: VoIP providers can obtain numbers directly under 47 CFR 52.15(g)(3) and must port them under 52.34, the rule that lets a business keep its main line when it moves, as our VoIP number guide explains. Common claims that conflict with the primary sources are set out below.

Are calls from VoIP numbers more likely to be scams?

Most VoIP calls are ordinary business calls, but the FCC told Congress in its December 23, 2025 TRACED Act report that its traceback experience shows a disproportionately large number of unlawful calls originate from VoIP providers. The reasons it gives are economic: VoIP resellers are cheap to set up, wholesale rates to US mobiles are under a penny per minute, and six-second billing makes short robocalls cheap.

The Industry Traceback Group (ITG), the USTelecom-led consortium registered under section 13 of the TRACED Act, identified 714 providers in 2024 tracebacks, 275 of them new. The FCC report adds that the ITG does not record which originators are VoIP providers, so no published figure gives a VoIP share of illegal calls.

What if your own phone system made the calls?

Then your client’s account is the VoIP caller in someone else’s traceback. The ITG reported that in about 7% of completed 2024 tracebacks, the originating provider said a customer’s own system or account had been compromised and used to send the traffic (ITG letter, May 1, 2025). The provider must answer each traceback within 24 hours of receipt, so contain the account and hand over records the same day.

1. Hour 0: Suspend or rotate the SIP credentials and restrict outbound calling. In Teams, change end-user PSTN calls from the default “International and Domestic” to “Domestic” or “None” (Microsoft Learn).
2. Same day: Ask the carrier to block outgoing international calls the client does not need. The FCC already advises any line that never calls abroad to have the carrier block outgoing international calls.
3. Within 24 hours: The voice provider must fully answer each traceback request. The duty runs 24 hours from receipt; a request arriving outside 8 a.m. to 5:30 p.m. local time on a business day counts as received at 8 a.m. the next business day, and the clock pauses over weekends and federal holidays (47 CFR 64.1200(n)(1)). Send call records and containment steps the same day.
4. At least 14 days: Provider’s window to investigate an FCC Notification of Suspected Illegal Traffic, then block it. Under 64.1200(n)(2), the provider must then block the identified traffic and substantially similar traffic, which can cut off the compromised account’s calls.
5. 30 days: Downstream providers stop accepting a provider’s traffic after a Final Determination Order. Under 64.1200(n)(3), this is the step that ends a provider’s direct US traffic when it ignores the FCC notice.

Once calls stop, check the controls below on every client phone system, not only the one that was hit. NIST SP 800-58 (January 2005) calls failing to change default passwords one of the most common errors.

Put three items in each client agreement before an incident: who pays for fraudulent call charges, how many hours the MSP has to notify the voice provider, and who keeps the call detail records the provider needs for its 24-hour traceback answer under 64.1200(n)(1). Without them, the first traceback becomes a billing dispute.

What do STIR/SHAKEN attestation levels A, B and C mean?

STIR/SHAKEN is the caller ID authentication framework that 47 CFR 64.6301 required voice service providers to deploy in their IP networks by June 30, 2021. The originating provider signs each SIP call with a level: A means it knows the customer and the customer may use the number, B means it knows the customer only, and C means it only received the call at a gateway.

The signature passes these points before any label reaches your screen:

1. Originating provider: Signs the SIP call with attestation A, B or C and its own certificate (47 CFR 64.6301(a); RFC 8588).
2. Intermediate provider: Passes the signed caller ID on unaltered (47 CFR 64.6302(b)).
3. Gateway provider: Signs foreign calls that carry a US number, usually at level C (47 CFR 64.6302(d); FCC 20-42, para. 8).
4. Terminating provider: Verifies the signature and may block or label the call using analytics (47 CFR 64.6301(a)(3); 64.1200(k)(3)).
5. Your phone or platform: Shows the carrier label, any verification mark, or a Teams Spam likely tag (FCC 20-42, para. 54; Microsoft Learn).

An A attestation is a statement about the customer relationship, not about the call’s legality. The FCC said Lingo Telecom gave A-level attestation to spoofed AI-voice robocalls whose number belonged to someone other than its customer; the Commission proposed a $2,000,000 forfeiture in May 2024, and Lingo settled with the Enforcement Bureau on August 21, 2024 (FCC DA 25-1100). In its May 2025 letter, the ITG reported 336 tracebacks of A-attested calls whose signer did not match the originating provider (ITG letter).

Providers certify their STIR/SHAKEN status (full, partial or none) in the FCC’s Robocall Mitigation Database under 47 CFR 64.6305, and other providers may not accept traffic directly from one missing from it. On December 10, 2024 the Enforcement Bureau ordered 2,411 filers to cure deficient certifications, then removed 185 of them on August 6, 2025 and more than 1,100 more on August 25, 2025 (FCC DA 25-694; DA 25-737).

That makes the RMD the first buying check, before any shortlist from a VoIP system comparison:

1. Search each provider in the RMD listings and note full, partial or no STIR/SHAKEN; one certifying none is not signing your calls itself.
2. Confirm the filing was not removed: under 64.6305(g) a removed provider cannot hand calls directly to other US providers.
3. Ask which attestation level your numbers, including ported ones, will get, and add the answer to our business phone system buying checklist.

When is caller ID spoofing illegal?

Caller ID spoofing is illegal in the US when someone knowingly transmits misleading or inaccurate caller ID with intent to defraud, cause harm or wrongfully obtain anything of value. That is the Truth in Caller ID Act, codified at 47 U.S.C. 227(e) and implemented in 47 CFR 64.1604. Displaying a company’s main or toll-free callback number is legal, and so is blocking your number entirely.

Telemarketers carry an extra duty: under 47 CFR 64.1601(e) they must transmit a calling number, and a name where their carrier supports it, and may not block caller ID. Illegal spoofing carries an FCC forfeiture of up to $14,432 per violation under 47 CFR 1.80(b)(4); the FCC cancelled its 2026 inflation adjustment (91 FR 39613). On September 30, 2024 it imposed $6,000,000 on Steve Kramer for spoofed deepfake-voice robocalls before the New Hampshire primary (FCC DA 25-1100).

How do you identify a VoIP caller?

You identify a VoIP caller by checking authenticity, not technology. Read the label and who applied it, treat the digits as unproven because neighbor spoofing often copies the first six digits of your number, and confirm identity by calling back on a number from your own records. A business phone system can also read the STIR/SHAKEN attestation that travels with the call.

1. Read the label, then the source. Carriers may block calls using reasonable analytics that weigh caller ID authentication, with no line-item charge (47 CFR 64.1200(k)(3)). The FCC notes a labeled number may itself be spoofed.
2. Do not require a verification mark. The FCC declined to mandate any display of STIR/SHAKEN results in March 2020 (FCC 20-42, para. 54), so a missing checkmark is not evidence of fraud.
3. Treat the digits as unproven. Neighbor spoofing often copies the first six digits of your number (FTC, July 2023), and a carrier lookup can name the wrong carrier after a port under 47 CFR 52.34.
4. Verify out of band. Hang up and call the number on your statement or the organisation’s website, as the FCC spoofing guide advises.
5. On a SIP phone system, read the attestation. If your trunk provider passes the Identity header to your session border controller or PBX, the PASSporT “attest” claim shows A, B or C (RFC 8588, section 4).

Since February 2024 the FCC treats AI-generated voices as artificial voices under the TCPA, so a cloned-voice robocall, the phone form of the attacks tracked in our phishing statistics report, needs prior consent like any recording (FCC DA 25-1100).

How do you fix “Spam Likely” on your business numbers?

Register the numbers, dispute each live label, and fix what your provider sends. The Free Caller Registry passes one free registration, up to 20 numbers typed in or more by file, to First Orion, Hiya and TNS; Verizon, AT&T and TNS each run a dispute form; and your provider controls the attestation and caller name. The Registry and Verizon both warn that a submission does not guarantee a label changes.

1. Register with the Free Caller Registry. At freecallerregistry.com, verify a business email, give the address, call purpose and monthly call volume, then type in up to 20 numbers or upload an xlsx or txt file under 100 KB to register more. The terms say the form is for businesses calling on their own behalf: “If you are registering numbers on behalf of another business, you must contact the call protection providers directly.” So the client files the form, or the MSP writes to First Orion, Hiya and TNS at the addresses the Registry lists.
2. Register with Hiya and First Orion. Hiya verifies the business within 24 hours and vets numbers in under a day, though changes can take a few more days to reach carriers; First Orion’s Watchlist, launched October 13, 2026, shows whether a number is tagged Potential Spam on T-Mobile and why.
3. Dispute each live label. Use Verizon’s spam feedback form business option, AT&T’s att.com/reviewmycalllabel link (a Hiya ticket) and TNS’s reportarobocall.com.
4. Ask your provider for A attestation. FCC 20-42 (para. 29) records commenters’ concern that calls sent through a provider other than the one that assigned the number struggle to get A, and since September 18, 2025 the provider makes every attestation decision itself (47 CFR 64.6301(b)). Ask whether ported numbers get A.
5. Set the caller name with your provider. Registration data is not used to deliver caller ID name, per the Registry terms; in Teams, a calling party name of up to 200 characters is set in the caller ID policy, though downstream systems may show fewer (Microsoft Learn).
6. Escalate blocked calls. If calls are blocked outright, use the terminating carrier’s single point of contact under 47 CFR 64.1200(k)(8); on caller ID authentication disputes it owes a status update within 24 hours.

For an MSP, quote this as a fixed-scope project per client: the client’s staff file the Registry form (or the MSP contacts the three firms directly), the MSP runs steps 2 to 6, and the client signs off which numbers dial out. The Registry says a second submission of the same number adds no redress.

Should you answer, block or report the call?

Answer when the number matches your records and the caller asks for nothing sensitive; send it to voicemail when your carrier labels it spam or you do not know it; report when a prerecorded sales call arrives without written consent, when your own number is spoofed, or when money or data is lost. The table and flowchart apply the FCC and FTC guidance step by step.

1. Block the number on the handset or PBX. The FTC notes a phone may limit how many numbers you can block.
2. Turn on carrier analytics blocking. Under 47 CFR 64.1200(k)(3), it must offer an opt-out and carry no line-item charge.
3. Check for wanted incoming calls you lost. A carrier running an opt-in or opt-out blocking program must, on request and free, list within 3 business days the calls to your number it blocked in the prior 28 days (47 CFR 64.1200(k)(10)).
4. Report the call through the channels in the table below. The FCC uses complaints for enforcement under the TCPA and the Truth in Caller ID Act, not to resolve individual cases.
5. If your own number is spoofed, add a notice to your voicemail greeting, as the FCC suggests, and ask your carrier to block calls claiming to come from any inbound-only number, such as a support line (47 CFR 64.1200(k)(1)).

How we compiled this

We compiled this page in October 2026 from 38 primary documents: eCFR sections current to October 16, 2026, 47 U.S.C. 227, FCC orders, reports and consumer pages, FTC pages, the registration and dispute pages of six registry, carrier and analytics firms, NIST SP 800-58, RFC 8588 and Microsoft Learn, plus FCC Form 477 data from our VoIP statistics report. We did not test any carrier service or blocking app, and offer general information, not legal advice.

Frequently asked questions

What is the difference between Scam Likely and Potential Spam?

On T-Mobile, Scam Likely marks calls it treats as likely fraud, while Potential Spam marks unwanted solicitation from numbers not intended for you; dialing #662# turns on Scam Block for Scam Likely calls (T-Mobile). Verizon uses Potential Spam, Potential Fraud, Robo caller and SPAM?, and says any other label did not come from Verizon (Verizon).

Will registering my number show my business name on calls?

No. The Free Caller Registry states that neither its analytics partners nor their carriers use registration data to deliver caller ID name (Free Caller Registry). The name comes from the CNAM your voice provider sets; Microsoft Teams supports a calling party name of up to 200 characters, though downstream systems may show fewer (Microsoft Learn). Hiya and First Orion offer branded calling as a separate upgrade.

Should I call back a missed call from an unknown VoIP number?

Not if it rang once and you do not recognize it. The FCC warns of one-ring scams that use international numbers whose first three digits look like US area codes, such as 232 for Sierra Leone and 809 for the Dominican Republic; calling back can bring connection and per-minute fees (FCC one-ring guide). Lines that never call abroad can have international calling blocked.

How do I report a spam text from a VoIP number?

Forward it to 7726 (SPAM), which most mobile carriers accept, and do not click its links (FCC). Since September 3, 2024, FCC rules require mobile providers to block texts claiming to come from numbers on a reasonable do-not-originate list, such as unused or invalid numbers (FCC DA 25-1100). Repeated texts can also go to the FCC complaint form.

How long does Do Not Call registration take to work?

Your number appears on the National Do Not Call Registry the next day, but the FTC says sales calls can take up to 31 days to stop, and registration never expires; the FTC removes a number only if it is disconnected and reassigned or you ask (FTC FAQ). It covers personal numbers only and does not stop scammers, who ignore the Registry.

Why does my business get labeled on one carrier but not another?

Each carrier and analytics firm scores numbers independently. The Free Caller Registry warns that registration does not guarantee redress from analysis each provider does on its own (Free Caller Registry), and Verizon says its submissions may not change future labels (Verizon). Register once, then dispute on the specific network where clients see the label.

Sources

1. The Uptime Report, VoIP Statistics 2026 (FCC Form 477 data). Accessed October 2026.
2. eCFR, 47 CFR 9.3 Definitions (interconnected VoIP service). Accessed October 2026.
3. eCFR, 47 CFR 52.15 Central office code administration (numbering applications). Accessed October 2026.
4. eCFR, 47 CFR 52.34 Local number porting to and from interconnected VoIP providers. Accessed October 2026.
5. eCFR, 47 CFR 64.1200 Delivery restrictions (call blocking, tracebacks). Accessed October 2026.
6. eCFR, 47 CFR 64.1601 Delivery requirements for caller ID. Accessed October 2026.
7. eCFR, 47 CFR 64.1604 Prohibition on inaccurate or misleading caller ID. Accessed October 2026.
8. eCFR, 47 CFR 64.6301 Caller ID authentication. Accessed October 2026.
9. eCFR, 47 CFR 64.6302 Caller ID authentication by intermediate providers. Accessed October 2026.
10. eCFR, 47 CFR 64.6305 Robocall mitigation and certification. Accessed October 2026.
11. eCFR, 47 CFR 1.80 Forfeiture proceedings (2025 inflation adjustment). Accessed October 2026.
12. Legal Information Institute, 47 U.S.C. 227 Restrictions on use of telephone equipment. Accessed October 2026.
13. FCC, Call Authentication Trust Anchor Report and Order, FCC 20-42 (March 31, 2020). Accessed October 2026.
14. FCC, Report to Congress on Robocalls and Transmission of Misleading or Inaccurate Caller ID, DA 25-1100 (December 23, 2025). Accessed October 2026.
15. Industry Traceback Group, letter to the FCC on private-led traceback efforts (May 1, 2025), DA 25-1100 attachment. Accessed October 2026.
16. FCC Enforcement Bureau, Robocall Mitigation Database Filers removal order, DA 25-694 (August 6, 2025). Accessed October 2026.
17. FCC Enforcement Bureau, Robocall Mitigation Database Filers removal order, DA 25-737 (August 25, 2025). Accessed October 2026.
18. Federal Register, FCC Notification of Cancelled Adjustment of Civil Monetary Penalties for Inflation, 91 FR 39613 (June 30, 2026). Accessed October 2026.
19. FCC, Caller ID Spoofing consumer guide (reviewed November 13, 2024). Accessed October 2026.
20. FCC, Stop Unwanted Robocalls and Texts consumer guide (reviewed February 27, 2026). Accessed October 2026.
21. FCC, ‘One Ring’ Phone Scam consumer guide (reviewed May 15, 2019). Accessed October 2026.
22. FCC, Call Authentication (STIR/SHAKEN) overview. Accessed October 2026.
23. FCC, Robocall Mitigation Database. Accessed October 2026.
24. FCC, Robocall Mitigation Database listings. Accessed October 2026.
25. FCC Consumer Complaint Center, Unwanted Calls/Texts: Phone. Accessed October 2026.
26. FTC, How to Block Unwanted Calls (July 2023). Accessed October 2026.
27. FTC, National Do Not Call Registry FAQs (September 2023). Accessed October 2026.
28. Free Caller Registry, registration form and terms (October 2026). Accessed October 2026.
29. Hiya, Number Registration (October 2026). Accessed October 2026.
30. First Orion, Free Business Number Registration and Watchlist (October 2026). Accessed October 2026.
31. Verizon, voice spam feedback form (October 2026). Accessed October 2026.
32. TNS, Report a Robocall feedback form (October 2026). Accessed October 2026.
33. AT&T, review my call label link (redirects to a Hiya support ticket, October 2026). Accessed October 2026.
34. T-Mobile, ScamShield (October 2026). Accessed October 2026.
35. NIST, SP 800-58 Security Considerations for Voice Over IP Systems (January 2005). Accessed October 2026.
36. IETF, RFC 8588 PASSporT Extension for SHAKEN (May 2019). Accessed October 2026.
37. Microsoft Learn, Manage caller ID for users (October 2026). Accessed October 2026.
38. Microsoft Learn, Outbound calling restriction policies (October 2026). Accessed October 2026.
39. Microsoft Learn, More about Calling Line ID and Calling Party Name (September 2026). Accessed October 2026.