The Federal Communications Commission (FCC) is now requiring phone carriers to block other carriers that have not implemented anti-robocall features.

The FCC has been cracking down on robocalls, requiring carriers to implement the STIR/SHAKEN protocol. STIR/SHAKEN is a way for carriers to verify the authenticity of a call, pass that check on to the next carrier for further verification, and then confirming to the recipient that the call is verified or possibly spam.

The FCC previously set September 28 as the deadline for carriers to have the mitigation efforts in place. Now that the deadline has arrived, carriers will be required block those carriers that have failed to meet the FCC’s deadline.

“The FCC is using every tool we can to combat malicious robocalls and spoofing – from substantial fines on bad actors to policy changes to technical innovations like STIR/SHAKEN,” said Acting Chairwoman Rosenworcel. “Today’s deadline establishes a very powerful tool for blocking unlawful robocalls. We will continue to do everything in our power to protect consumers against scammers who flood our homes and businesses with spoofed robocalls.”