alt Hacker NewsAccording to a defcon talk, spammers just make sure all their spam gets routed through legacy TDM systems which discard the shaken/stir header because they're too old to support it. The other side then re-adds a "we got this from somewhere that didn't support this header" header.
> legacy TDM systems
Easy fix. It should be opt-in to accept a call that is routed through one of these. I know they allow it so some grandma in rural France that still uses a dial phone on a copper line that hasn't been touched since 1962 can call her son in New York, but for the rest of us who are not in that situation, we can just blacklist all those calls and lose nothing. This would even fix spam for the people who opt-in, because so few people have grandmas in rural France that it's not worth it for the spammers to bother anymore.