What are your opinions regarding intermediate carriers signing unattested calls? Not to say they are the source of the call, but to facilitate tracebacks and take accountability for transiting the call from whatever upstream didn't sign or preserve the signature. Calvin Ellison Systems Architect calvin.ellison at voxox.com +1 (213) 285-0555 <http://voxox.com> <https://www.facebook.com/VOXOX/> <https://www.instagram.com/voxoxofficial/> <https://www.linkedin.com/company/3573541/admin/> <https://twitter.com/Voxox> The information contained herein is confidential and privileged information or work product intended only for the individual or entity to whom it is addressed. Any unauthorized use, distribution, or copying of this communication is strictly prohibited. If you have received this communication in error, please notify me immediately. On Tue, Jul 5, 2022 at 11:47 AM Zilk, David <David.Zilk at cdk.com> wrote:
Mark,
Agreed. I guess it comes down to how to decide who the originating carrier is that should be doing the attestation.
As an intermediate carrier, Bandwidth should just pass through whatever Identity header they get; but if there is no Identity header (stripped header, TDM link in the path, originating carrier not attesting, etc.) then the only assumption they can make is that the partner originated the call (even if they didn?t) and ?B? is the only proper attestation they can apply.
Bandwidth making the assumption that they are an intermediate carrier (and the unattested calls came from some other (non-partner) service provider) isn?t a reasonable assumption.
David
*From:* Mark Lindsey <lindsey at e-c-group.com> *Sent:* Tuesday, July 5, 2022 10:16 AM *To:* Zilk, David <David.Zilk at cdk.com>; voiceops at voiceops.org *Subject:* Re: [VoiceOps] [EXTERNAL] Identity Header Test Tool
The primary problem to fix, in this scenario, is that Term Provider 2 is stripping the Identity header, and therefore violating 47 CFR ? 64.6302(a) <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.ecfr.gov_current_ti...>. So many engineers have configured SBCs to strip every header except the handful they want to carry, but *Identity* needs to be added to those lists.
The secondary problem to fix is that 47 CFR ? 64.6302(b) <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.ecfr.gov_current_ti...> allows intermediate providers to legally opt out of STIR/SHAKEN in any practical fashion.
I am speculating in the example call flow shown below, but I wouldn't see Bandwidth's behavior as a key problem. The ATIS destination of the C-level attestation is for a situation that, like flying pigs, doesn't appear to occur anywhere in reality. Nobody just accepts SIP traffic from random, anonymous sources for termination. I'm glad Bandwidth is adding the attestation that it can add.
*Mark R Lindsey **|* *SMTS **|** +1-229-316-0013 **|* *mark at ecg.co* <mark at ecg.co>
Schedule a meeting <https://urldefense.proofpoint.com/v2/url?u=https-3A__ecg.co_lindsey_schedule...>
On Jul 5, 2022, at 13:01, Zilk, David <David.Zilk at cdk.com> wrote:
If that is the case, a scammer that should be either attested C, or not attested at all can game the system and upgrade their calls to any customer of Bandwidth to B. Granted, B attestation isn?t much better than nothing, but still it violates both the intent and the letter of the law.
David Zilk
CDK Global/IP Networked Services
*From:* Mark Lindsey <lindsey at e-c-group.com> *Sent:* Tuesday, July 5, 2022 9:58 AM *To:* Zilk, David <David.Zilk at cdk.com> *Cc:* voiceops at voiceops.org *Subject:* Re: [VoiceOps] [EXTERNAL] Identity Header Test Tool
I expect Bandwidth is attesting that they know the identity of the SIP trunking provider that sent your call to Bandwidth.
CDK Global -> [term provider 1] -> [term provider 2, Strips Identity Header] -> [term provider 3] -> [Bandwidth.com <https://urldefense.proofpoint.com/v2/url?u=http-3A__Bandwidth.com&d=DwMFAg&c...> ]
...And term provider 3 is a customer of Bandwidth.com. <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.bandwidth.com_blog_...>
*Mark R Lindsey **|* *SMTS **|** +1-229-316-0013 **|* *mark at ecg.co* <mark at ecg.co>
Schedule a meeting <https://urldefense.proofpoint.com/v2/url?u=https-3A__ecg.co_lindsey_schedule...>
On Jul 5, 2022, at 12:19, Zilk, David <David.Zilk at cdk.com> wrote:
I am getting results from a test to the Bandwidth number that are confusing. It appears that our Identity header is not making it through to them, however the call does have an Identity header, certified by Bandwith, with B attestation. This is odd as we don't have any direct business relationship with Bandwidth. How can they claim B attestation?
David Zilk CDK Global/IP Networked Services
-----Original Message----- From: VoiceOps <voiceops-bounces at voiceops.org> On Behalf Of David Frankel Sent: Sunday, July 3, 2022 8:05 AM To: voiceops at voiceops.org Subject: [EXTERNAL] [VoiceOps] Identity Header Test Tool
CAUTION: This email originated from outside of the CDK organization. Exercise caution when clicking links or opening attachments, especially from unknown senders.
Last week I was forwarded a note from this list regarding tools to test and debug SHAKEN Identity headers. That prompted us to stitch together some modules we already had in an attempt to help.
What we have is at http://identity.legalcallsonly.org <https://urldefense.proofpoint.com/v2/url?u=http-3A__identity.legalcallsonly....>. You can call one of the test numbers listed on that page, and if we receive your header, we'll read you a six-digit code. Disconnect and then plug the code into the box on the web form, and we'll show you details of that Identity header.
Perhaps most importantly, you'll be able to see if the header we received is the one you sent. In addition, we parse the header and try to tell you if it is correctly formatted and valid.
Currently we have a couple of geographic DIDs and three toll-free numbers (each using different underlying providers). So far we aren't having a lot of success getting the Identity headers on the TFNs; we're working to improve that.
Suggestions welcome. We hope the tool provokes more discussion about best practices regarding making the Authentication Framework as functional and useful as possible.
Happy 4th of July!
David Frankel ZipDX LLC St. George, UT USA
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