Bank 2FA Blocks: Shortcodes & Wireless SIMs
Why Chase, Bank of America, Wells Fargo, and PayPal reject virtual numbers for two-factor authentication. FFIEC and NIST standards.
Systematic Delivery Diagnostic Tree
NIST SP 800-63B Authentication Guidelines
Federal guidelines classify VoIP SMS as a restricted authentication authenticator due to susceptibility to interception and credential stuffing.
Early Warning Services (EWS) Account Verification
Major banks verify that the phone number on file matches the subscriber name and physical address on the cellular carrier contract via credit bureau lookup APIs.
SIM Swap & Port-Out Fraud Protection
Banks query carrier databases for recent SIM change timestamps. If a SIM swap occurred within 48 hours, authentication codes are withheld automatically.
Frequently Asked Questions
Why won't my bank send an SMS code to a temporary number?
Banks enforce strict regulatory standards that cross-reference the phone number against your identity and require physical cellular carrier authentication.
What is the recommended 2FA method for banking?
Hardware security keys (FIDO2/WebAuthn) or time-based authenticator apps (TOTP) are strongly recommended over SMS 2FA.