>Upstream agreements already block Mobile carriers. Further, SMS from Short Codes are blocked by default. You can only receive SMS from long-numbers. Eg Wicker

>Upstream agreements already block Mobile carriers. Further, SMS from Short Codes are blocked by default. You can only receive SMS from long-numbers. Eg Wicker . I've built a very similar product to ZipWhip. These restrictions are likely enforced by ZipWhip, there is nothing structural at the NetNumber or other level that technically prevents you from taking over SMS message routing or receiving messages from short codes on mobile numbers. Submit the SPID change to NetNumber and you're off and running! The secujrity It is worth noting that the mobile carriers will periodically "reset" these changes to fix the routing (T-Mobile is one of the more aggressive ones here) and that continued violations by MVNOs like Sakari would eventually result in a loss of access for them. In Sakari's case, they were doing no due diligence or much to prevent the fraud. My own company's workflow for landlines placed a telephone call to the customer's number to give them a code to use in the registration process (remember, the attack noted in the article doesn't port the number, it just reroutes SMS). For toll-free numbers, we required legal documentation to prove that you owned the number. We also didn't allow any mobile numbers to be registered at any time.