How STIR/SHAKEN Impacts Your Caller ID

• If your business struggles with calls labeled “Spam Likely” or “Scam Risk,” you may wonder why. Often, the answer lies in how STIR/SHAKEN impacts caller ID. This framework was built to protect consumers from spoofed calls. However, when carriers rely on outdated systems like SS7, even legitimate businesses can face problems. Let’s look at how STIR/SHAKEN works, why attestation sometimes gets lost, and how to protect your caller ID reputation.

What Is STIR/SHAKEN and Why It Matters

STIR means Secure Telephony Identity Revisited. SHAKEN stands for Signature-based Handling of Asserted Information Using toKENs. Together, they create a digital signature for outbound calls. That signature confirms the caller is authorized to use the number. The receiving carrier can then check the signature before delivering the call.

Each call receives one of three attestation levels:

 – A (Full Attestation): Caller is verified and authorized to use the number.
 – B (Partial Attestation): Caller is known, but ownership of the number is unclear.
 – C (Gateway Attestation): Caller is not verified or came through an untrusted gateway.

Carriers, regulators, and apps use these levels to decide whether a call appears safe, suspicious, or risky.

SS7 Legacy Routes: The Weak Link

Even when a call leaves your provider with full attestation, that does not mean it will arrive intact. Many carriers still rely on SS7 legacy routes, which were built before STIR/SHAKEN.

When a call moves through these older systems, the digital passport can be removed. As a result, the receiving carrier sees the call without attestation or with a downgraded status. Consequently, your call may appear less trustworthy and attract a negative label.

This weak link is another example of how STIR/SHAKEN impacts caller ID in ways outside your direct control.

Why Labeling Hurts Your Business

Labels tied to missing or weak attestation can harm your business:

•  – More labels: Calls without A-level attestation are more likely to display “Spam.”
•  – Lower trust: Customers ignore calls that seem suspicious.
•  – Lost compliance: Critical calls may fail to reach consumers, creating legal and financial risks.
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In short, labeling reduces answer rates and increases costs.

Steps to Protect Caller ID Reputation

You can take action now:

1. Ask Your Provider

• Do you sign my calls with A-level attestation?
• Do my calls travel through SS7 routes that may strip attestation?

2. Monitor Your Numbers

Use Numberlab to track how your numbers appear across carriers. Frequent checks show if labels are spreading or if specific routes cause problems.

3. Improve Dialing Practices

• Stick to numbers you own and control.
• Keep volume consistent and avoid frequent number swaps.
• Check out a comprehensive best practice guide here 

4. Test Your Attestation for Free

• ClearlyIP Attestation Service: Call their test line and see your attestation level.
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• IDT Express Verification Tool: Enter your number and check the signing details.
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These free tools provide a quick snapshot. For deeper monitoring, combine them with services like Numberlab.

Final Thoughts

STIR/SHAKEN raised the bar for caller identity, but it isn’t flawless. Legacy SS7 routes and uneven adoption often cause attestation loss, leading to unfair labels.

To protect your business:

•  – Ask providers about routing and attestation.
•  – Track your numbers regularly.
•  – Use monitoring tools like Numberlab to stay ahead of problems.
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By combining good dialing practices with active monitoring, you can keep your numbers trusted and your calls answered.