[HN Gopher] Ask HN: Why do I get robocalls from recently-called ...
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       Ask HN: Why do I get robocalls from recently-called area codes?
        
       Over the past few weeks, I've started receiving robocalls from area
       codes that I happen to have just called or received a call from.
       At first I thought this was just me noticing a pattern that wasn't
       really there, but when I looked back at my phone records I could
       see that I had literally never received a phone call from either of
       these area codes, and that within a day of talking with someone in
       that area code I started getting robocalls.  Has anyone else
       experienced this? How would robocallers get this information --
       interception, buying it from my cell phone company, or something
       else?  Even if they're just buying a list of area codes I've talked
       to, this seems completely inappropriate. And if they're getting the
       actual numbers, that's even worse.
        
       Author : gnicholas
       Score  : 29 points
       Date   : 2022-02-11 21:49 UTC (1 hours ago)
        
       | rsync wrote:
       | Which carrier do you use ?
        
         | gnicholas wrote:
         | It's an MVNO, which makes me extra suspicious that the reason
         | they have low prices is because they're selling my information.
        
       | james-skemp wrote:
       | We might need more information.
       | 
       | I get a number of local code spam calls, but have seen an
       | increase in state code calls.
       | 
       | Are the area codes you're seeing local to you, or distant? Or,
       | what's the likelihood that someone in your region would be
       | calling the same area codes?
        
         | gnicholas wrote:
         | I live in the Bay Area, and the area codes are from SoCal (not
         | one of the major ones) and Delaware.
         | 
         | I previously received robocalls from my local area code, and
         | random ones from around the country. But not from these area
         | codes.
        
       | slt2021 wrote:
       | does anyone know who is the telecom company that provides routes
       | the calls from the robocallers?
        
         | techsupporter wrote:
         | There are hundreds, you'd have to play whack-a-mole with myriad
         | VoIP and second- and third-tier wireline providers to get them
         | all. And that presupposes that the accounts are even
         | legitimate. A lot of robocalls are delivered through hacked SIP
         | credentials.
         | 
         | I know people like to pick on them because they do seem to turn
         | a blind eye to all but the most egregious spammers, but Twilio
         | is only the source of a lot of spam calls because they are a
         | large carrier in their own right. It's like all of the people
         | moaning about Californians being the most common place of
         | origin for people moving to their area; that's true, because
         | California has the most number of people.
        
           | maxerickson wrote:
           | If it's literally just hundreds they should be able to handle
           | it no problem. Even if they had to staff up to do it, no
           | problem.
        
       | altairprime wrote:
       | If you look up the carrier of each number you called, are there
       | any commonalities across them?
       | 
       | Have you opted out of CPNI resale in your cellular carrier's
       | preferences system?
        
       | poletopole wrote:
       | Welcome to the club. They know when I get off work and wake up
       | now.
        
       | faebi wrote:
       | Maybe their spam filters block many of these robo calls but they
       | let them through if you had some recent contact in the same
       | area/digits?
        
       | walrus01 wrote:
       | for voice calls, the best thing I ever did was set up my own
       | asterisk system with a DID that answers as an IVR saying
       | something like "you have reached $NAME, this is an anti-spam
       | system, please confirm you are a human by entering the digits
       | five three zero nine to be connected".
       | 
       | If people then put in the DTMF tones for 5309, or whatever code
       | it might be this month, it initiates an outbound call to my
       | actual cellphone and bridges the calls together.
       | 
       | In many cases I don't give out my direct cellphone number to 3rd
       | parties, I only give out the DID of the system with the filtering
       | IVR on it.
        
         | gruez wrote:
         | Does this system pass through the original caller's info on
         | caller id?
        
         | h0l0cube wrote:
         | Seems like something people would pay for.
        
       | inetknght wrote:
       | As a counterpoint, I frequently get robocalls from area codes
       | near where I travel. I recently visited Virginia and received
       | robocalls from Virginia area codes for a while. A couple years
       | ago I visited California and received more than the usual number
       | of robocalls from California. A few years ago I visited Seattle
       | and received robocalls from Washington. I most recently moved
       | within Texas and the constant robocalls changed area codes to the
       | more common local one.
       | 
       | I really _really_ wish I could flag an incoming call to my
       | telecom provider and get paid money for it charged to the caller.
       | Then let the telecom provider prove that it was or wasn't
       | malicious.
        
         | dunham wrote:
         | So far I haven't had this issue. I am in Seattle (for years),
         | still have my 415 (San Francisco) phone number, and can still
         | filter spam by ignoring calls from 415.
         | 
         | If you don't mind sharing, which provider are you using? And,
         | if it is Verizon, have you opted out of data sharing?
        
           | inetknght wrote:
           | T-mobile. I've opted out of all sharing that I'm aware of.
           | But as I'm sure you're also aware, it's an endless fight;
           | modern "businesses" frequently reset settings, rename
           | settings, or add new settings with defaults that benefit them
           | instead of the customer.
        
       | Dwolb wrote:
       | To piggyback on this thread, does anyone know if I can block a
       | specific phone number provider (e.g. block all Twilio calls)?
        
         | jedberg wrote:
         | I think you can do that ironically if you use Twillio as your
         | primary incoming phone number.
        
         | larrymcp wrote:
         | Oh my goodness, my employer uses Twilio as our phone provider.
         | If people started blocking Twilio, then for example a customer
         | might call our support team to ask a question, and then after
         | we research the issue we would we unable to call him back. So I
         | sure _hope_ that doesn 't become a thing... whew
        
           | kylec wrote:
           | Well if Twilio is facilitating robocalls, I hope it does
           | become a thing. Then maybe they'd want to stop robocallers
           | from using their service.
        
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       (page generated 2022-02-11 23:00 UTC)