Aaron,

 

If I understand you correctly, you are dealing with a fairly conventional 
call-forwarding situation, and that is addressed in the SHAKEN standards. It 
does not have anything to do with an FCC “crackdown.”

 

The standards (ATIS 1000085) define something called a DIV passport – this is 
an additional signature (IDENTITY header) that is generated by the service 
provider responsible for forward (DIVerting) the call. It generally is used in 
conjunction with the SIP DIVERSION header.

 

Sansay has a nice write-up about it here:

https://support.sansay.com/t/p8hctyw/diversion-div-passport

 

I do see mention of the DIV passport on this Twilio page:

https://www.twilio.com/docs/voice/trusted-calling-with-shakenstir

 

Whether your systems (and those of the provider receiving the forwarded call) 
support DIV ppt is another matter.

 

Forwarding is (still) perfectly legal and you don’t need to “spoof” anything 
when following the standards.

 

David

 

From: Aaron C. de Bruyn via VoiceOps <[email protected]> 
Sent: Tuesday, January 6, 2026 3:54 PM
To: Mary Lou Carey <[email protected]>
Cc: Pinchas Neiman <[email protected]>; Mark R Lindsey, ECG 
<[email protected]>; [email protected]
Subject: [VoiceOps] Re: Services that rely on Caller ID spoofing?

 

Unfortunately in this situation the 3rd-party company expects us to receive 
calls from patients and instead of sending them to voicemail after-hours, we 
forward the call on to them.

That would require us to get permission to "spoof" numbers from tens of 
thousands of patients.

 

...or...if the 3rd-party company wasn't completely incompetent, have us set up 
a SIP or IAX trunk directly to them that does allow us to pass the call to them 
without going over the PSTN.

 

-A

 

 

On Tue, Jan 6, 2026 at 2:50 PM Mary Lou Carey <[email protected] 
<mailto:[email protected]> > wrote:

There are certain circumstances where caller ID spoofing is allowed. For 
example, in the situation where a doctor may be calling a patient after hours. 
They can change the doctor's cell phone number to be the phone number of the 
medical office the doctor works for. What people are not allowed to do is to 
spoof a number that they do not have permission to use. 

What carrier "owns" the number is highly debatable these days because there's 
multiple players.

1. The ILEC / CLEC / IPES / Wireless carrier that the NPA-NXX-X was assigned to.

2. The carrier who manages the TN under their LRN. (In ported TN situations)

3. The reseller who pays an upstream carrier for the DID service. (The DID may 
have been resold multiple times so the OCN associated with the LRN does not 
necessarily match the OCN of the carrier that manages the assignment of TNs. 

Whoever has the direct connection with the end user customer has the 
responsibility of ensuring that the TN is not spoofed in situations that are 
illegal.

 

MARY LOU CAREY 
BackUP Telecom Consulting 
Office: 615-791-9969 
Cell: 615-796-1111

 

On 2025-11-24 12:00 PM, Pinchas Neiman via VoiceOps wrote:

I think it's pretty clear that we are victims of crediting the holder instead 
of the owner, the definition of number ownership, the "Deed", must be decoupled 
from holding it. This should not be a matter of provider to provider 
verification, but a global record that entity X may use that phone number for 
caller ID.

 

Side note, hackers are hackers because they view themselves as experienced 
troublemakers, the standard cowboy will not give up his career just because a 
tech person earns more than him, although some smarter do, and some hackers are 
getting smarter in prison.

 

 

 

 

On Mon, Nov 24, 2025 at 3:30 PM Mary Lou Carey via VoiceOps 
<[email protected] <mailto:[email protected]> > wrote:

I think the intent to block spoofing is to prevent people from using telephone 
numbers they do not own. I once had a client that had the FBI show up on his 
doorstep because they said they traced a call back to his company. The number 
they were interested in was an unallocated TN in his PBX. Apparently someone 
had gotten ahold of that TN and was using it for nefarious purposes. 

Hackers are creative, I'll give them that. However, I'll never understand why 
they can't use their skills to make money legally. Why does one need to make 
mountains of money illegally when they can make enough to support themselves 
legally? Many create such a boatload of damage within a small amount of time 
that their poor innocent victims are detrimentally impacted by. I guess they 
don't care who they hurt. One can only hope Karma comes calling for them one 
day and reimburses them ten fold.  

MARY LOU CAREY 
BackUP Telecom Consulting 
Office: 615-791-9969 
Cell: 615-796-1111

 

On 2025-11-22 08:11 PM, Mark R Lindsey, ECG via VoiceOps wrote:

"Spoofing" is the standard term, even used in FCC docs, to mean that a person 
is placing a call from telephone number X using a voice service S, where calls 
placed from the PSTN to X don't always traverse service S. 

 

Of course this happens in conventional SIP trunking and wholesale interconnect 
all the time. It's so prevalent and normal that it's hard to even wrap your 
telecom head around what the FCC and the US congress even means. Why would you 
assume S is a symmetrical service for both placing and receiving calls? Does 
someone really think UPS or Bank Of America or even then local Memorial 
Hospital are seriously placing calls from exactly one place, or using a 
different "phone line" for each outbound call?

 

And they do understand that it's extremely common. Read some discussion in the 
latest FNRPM from last month —  

https://docs.fcc.gov/public/attachments/FCC-25-76A1.pdf

Attending conferences in this space and listening to FCC staffers, there is 
actually no push that I perceive to eliminate spoofing. But, there IS a push to 
eliminate the blind trust that anybody has the right to call from a telephone 
number, simply because they use it to populate the From header. In the latest 
suggestions from the FCC, what we might see are additional steps of vetting to 
determine you do have the right to place calls from a telephone number and the 
proper name that should be provided on that number. 

 

As of today, the "Know Your Customer" policy and practices of legitimate 
service providers will ensure the SP takes steps to confirm the right to place 
calls from the telephone numbers they use as the calling part number for 
outbound calls. 

 

In your example, Twilio was screening your calling party numbers. They probably 
have a list of telephone numbers from which you can call. I'm almost certain 
they have a process by which you can provide evidence you have the right to 
call from those numbers, and they'll update the screen list. 




Mark R Lindsey
Member of Technical Staff / VP
+1-229-316-0013
https://info.ecg.co/lindsey

 

 

On Wed, Nov 19, 2025 at 11:13 Aaron C. de Bruyn via VoiceOps 
<[email protected] <mailto:[email protected]> > wrote:

I'm not entirely up on the whole FCC Caller ID Spoofing crackdown that's going 
on, but I just ran into a 3rd party service for medical offices that expects us 
to spoof Caller ID. 

 

The service works like this:

* I  grab my cell phone (123-456-7890) and call my doctor/dentist/medical office

* It's after hours and they are busy with other calls

* Their phone system turns around and forwards my call to a 3rd-party number 
(say 111-222-3333) emitting my Caller ID info ("Aaron" <1234567890>)

* They see a call come in on 111-222-3333 and know it's for "Dr. Bob's Office", 
so their system accesses his patient database and looks for my patient record 
with the phone number 123-456-7890 and someone answers the call saying "Thanks 
for calling Dr. Bob's office".

 

My understanding is the ability to spoof Caller ID info across the PSTN is 
going away.

 

I tested, and I certainly can't do it with a Twilio SIP trunk.

 

The main reason I'm curious is I have a customer that has their own phone 
system that I help them manage (FreePBX linked to Twilio).  They just purchased 
an office that uses a 3rd-party phone provider (Weave) along with this 
3rd-party answering service, and they are somewhat upset that I can't make it 
work with their existing phone system.  The third-party answering service 
doesn't have any way of interconnecting other than spoofing Caller ID over the 
PSTN to a random number they assigned to the medical office.

 

Are services like this going the way of the dodo?  Are they having to set up 
private SIP trunks between clients to get this functionality?  Do some VoIP 
providers allow you to spoof Caller ID for this purpose under some sort of 
agreement?

 

Thanks,

 

-A

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-- 

Pinchas S. Neiman

Software Engineer At ESEQ Technology Corp.

Providing you reliable software solutions for any matter.

845.213.1229 #2



 

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