What Is VoIP?
VoIP (Voice over IP) routes calls via the internet. Scammers leverage cheap VoIP trunks to blast high-volume spoofed robocalls without carrier overhead.
VoIP — Voice over Internet Protocol — is technology that transmits phone calls as digital data packets over the internet, rather than through traditional circuit-switched telephone networks. While VoIP powers legitimate enterprise communications, it is simultaneously the primary infrastructure enabling the robocall epidemic: by eliminating per-call costs, VoIP enables operators to place millions of calls per hour at fractions of a cent per call.
Why VoIP Changed the Robocall Equation
Traditional PSTN telephony required physical switch infrastructure tied to geographic locations. VoIP eliminated these barriers, allowing autodialers to spoof caller IDs, hop across international gateways, and operate beyond the immediate reach of domestic law enforcement. Learn how commercial boiler rooms exploit this in our exposé: Inside Outbound Call Centers: Robocall Operations Explained.
VoIP and STIR/SHAKEN
The STIR/SHAKEN framework was designed to cryptographically sign call origins across US carrier networks. However, unauthenticated offshore VoIP calls enter at gateway points with C-level or missing attestation. Callro's Gauntlet Engine detects these gateway anomalies on-device and terminates unverified VoIP robocalls before the phone rings.
Frequently Asked Questions
What is VoIP?
VoIP (Voice over Internet Protocol) transmits phone calls as digital data over the internet instead of traditional telephone networks. It eliminates the geographic and cost constraints of traditional telephony, making it the primary infrastructure for robocall campaigns.
Why does VoIP enable so many robocalls?
VoIP eliminates the per-call cost of traditional telephony and allows Caller ID to be freely spoofed — robocall operators can place millions of calls per hour from anywhere in the world at near-zero cost. The combination of cheap, high-volume calling and spoofed caller identity makes enforcement extremely difficult.
How does STIR/SHAKEN address VoIP robocalls?
STIR/SHAKEN requires US carriers to cryptographically sign call identity, creating an attribution chain for calls within the US network. Calls from offshore VoIP infrastructure entering at gateway points typically receive C-level or no attestation — which is itself a strong spam signal that apps like Callro use for detection.
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