This Guy Found a Way to Block Robocalls When Phone Companies Wouldn’t

(from the article:)

In fact, late last week, the CTIA wrote the FCC to tell it that the kind of blacklist approach taken by Foss’s company wouldn’t work. According to the lobbying group, it raises privacy concerns—and causes other problems too.

“Even assuming an accurate database of blacklisted and whitelisted numbers can be compiled and maintained, the ease with which modern equipment and software can allow a caller to spoof a caller ID would present significant challenge,” the group says.

I thought the phone companies had access to more information than caller ID for the calls they handle. Surely you can't fake caller ID details to dodge your phone bill? I'd love it if they'd give out a star code we could all dial after a call we didn't want to receive that would, if enough people did it, disallow future calls from that entity from reaching any phone line for which a customer has requested the blocking of calls reported as bothersome. No exemptions for charities or politicians either.

Telecoms guy here.

Firstly CLI blocking is easy to get around. Faking CLI is very easy. There is a field within SIP that is refereed to as P-assert. The idea is that this field always contains the billable number.

However I know of at least 3 sip carriers you could sign up today with, have numbers within 10 minutes and they allow you to put ANY CLI and P-assert. Then you can bridge in to the TDM and almost untraceable.

CLI faking is very common. There is a requirement in the UK that no calls gets in to the network without a p-assert but the network is to complex these days, there is always a way to get a call in with what ever information you want

We have been working on a blacklisting service as well. we have 2 types, the personalized white and black list (so a parent can have a white list for their kids phone): i think i agree with the FCC that global block lists are a bad idea (too easy to get someones number blocked for lulz). The second looks up the CLI and checks a number of those "who is calling me sites" if the number is know for spam it does not get to the phone and starts reading the comments back to them about their number (cli will get round this). Both ways have issues. The reason I bring this up is because we become an MVNO and in turn run our own sim cards. This meant that we could have had the blacklist/whitelist without messing with the call flow to much. This also allowed you to dial 9 to block the last number that called you was sexy but meh too much work to run an MVNO and just no money in it.

We will see. Lots of changes will be happening in telecoms in the next 5-10 years. webRTC could flip the existing telecoms models on their heads, if only someone could get some traction.

Ramble Ramble, i rare have anything to say :/

Phone systems are also global. You create legislation and fines for not setting that value, but calls from legacy systems around the world still have to be supported. Or has anybody ever tried to call a number and got a "sorry, your phone is too old, you need to upgrade" response?

If you pick up the phone and say "Please put me on your courtesy do not call list", legitimate companies will stop calling you.

That leaves the you've won a free cruise/insurance/alarm scam companies, but they mostly don't call over and over again.

The point is not to argue with them about whether they should be calling you etc., it is to advertise yourself as a dead lead.

Do you expect a revealing answer to that question?

I don't think I'm suggesting something that wastes part of your life. What I suggest directly restores usefulness to the phone, and it likely forces the call center companies to report unsuccessful calls instead of no answers to their customers (and if done in large numbers it should have an impact).