6 ms·

TL;DR Don't pick up calls from unfamiliar numbers. It did help confirm a sneaking suspicion I've had, which is that robocalls spoof a caller ID number with you

by smarks 9y ago

TL;DR Don't pick up calls from unfamiliar numbers. It did help confirm a sneaking suspicion I've had, which is that robocalls spoof a caller ID number with your area code and prefix, to make it seem more familiar. Stories about people who manipulate telemarketers are amusing, and mobile minutes are mostly no longer scarce, but who has the time? Time and attention are the scarcest resources.

greenyoda 9y ago
"robocalls spoof a caller ID number with your area code and prefix, to make it seem more familiar" I discovered this pattern from robocalls on my cell phone. But it has exactly the opposite effect as intended: since I don't know anyone who has the same area code and prefix I do[1], I have 100% confidence that any call with a number like that is spam. And if I don't recognize the area code, or it's from a toll-free area code, it's also spam with 100% confidence. Fortunately, it's very rare for the spammers to leave a voicemail when I don't answer. [1] My city has 7 area codes and thousands of cellular prefixes - the odds of meeting someone with the same area+prefix are slim.
- enobrev 9y ago
  Same for me, since my phone number is more than a decade old and I haven't lived in the city where I obtained the number since 2012. I know people with numbers in the same area code, but definitely not with the same prefix. That said, just about every actual person I know texts before calling, if at least to check when might be a good time to call. Almost nobody calls outright, and if they do and I don't answer, there's always a follow-up text. The same code and prefix thing really seems to have picked up significantly in the last couple months. I have an app that catches most known spam calls, but tends to let these through, which I assume is one of the the underlying reasons for this type of spoofing.
russdill 9y ago
Surely telcos can do something to block calls coming from sources that don't own the number they are providing as caller id. Internet provides started doing this years ago with alien packets.
- MichaelGG 9y ago
  They often can't. A call can come in from any number of sources. Not to mention call forwarding and all that stuff. Telcos would love to kill robo dialing, but they usually do it by requiring a certain percentage of calls to complete and last longer than 6 seconds. If you want to hurt them, answer and hangup immediately.
  - russdill 9y ago
    Ah, that's why they don't say anything for 6 seconds.
- ahmeni 9y ago
  With number portability there is no solid "owner" of phone number blocks any more.
- toast0 9y ago
  There are a lot of legitimate reasons why a call from a number isn't coming from where you would be directing the call, so it's hard to fix it with a simple policy. What would be useful though is requiring something analogous to email received headers, combined with a real time method to report calls as spam/unwanted. If spam volume from an interconnecting carrier is too high, cut them off. Telco routing is a lot of twisty passages, but there are many fewer players than internet routing, so it should be easier to get bad apples off the network, as long as there is desire and some users are willing to provide feedback on calls.
  - posguy 9y ago
    Carriers already do this FYI, but it only gets you so far. Robocallers pay higher rates due to this, but they seem glad to pay.
sbov 9y ago
So this is what was happening... I have a "desirable" prefix and had been getting tons of calls from numbers with the same prefix - was wondering why the heck they would be calling me.
- smarks 9y ago
  Here's another article (really, radio transcript) on this phenomenon: http://www.npr.org/2017/07/31/540515367/familiar-looking-numbers-are-the-latest-twist-in-robocalls http://www.npr.org/2017/07/31/540515367/familiar-looking-num... One thing that this doesn't mention, but which I heard somewhere, is don't call that number back and ask "Why did you call me?" In case it isn't obvious, the caller IDs are spoofed using random numbers, and the person who has the number listed doesn't know their number is being used this way. One amusing anecdote from the NPR piece is the person who received a call with a caller ID of ... their own phone number!

by smarks 9y ago

greenyoda 9y ago

"robocalls spoof a caller ID number with your area code and prefix, to make it seem more familiar" I discovered this pattern from robocalls on my cell phone. But it has exactly the opposite effect as intended: since I don't know anyone who has the same area code and prefix I do[1], I have 100% confidence that any call with a number like that is spam. And if I don't recognize the area code, or it's from a toll-free area code, it's also spam with 100% confidence. Fortunately, it's very rare for the spammers to leave a voicemail when I don't answer. [1] My city has 7 area codes and thousands of cellular prefixes - the odds of meeting someone with the same area+prefix are slim.

enobrev 9y ago
Same for me, since my phone number is more than a decade old and I haven't lived in the city where I obtained the number since 2012. I know people with numbers in the same area code, but definitely not with the same prefix. That said, just about every actual person I know texts before calling, if at least to check when might be a good time to call. Almost nobody calls outright, and if they do and I don't answer, there's always a follow-up text. The same code and prefix thing really seems to have picked up significantly in the last couple months. I have an app that catches most known spam calls, but tends to let these through, which I assume is one of the the underlying reasons for this type of spoofing.

russdill 9y ago

Surely telcos can do something to block calls coming from sources that don't own the number they are providing as caller id. Internet provides started doing this years ago with alien packets.

MichaelGG 9y ago
They often can't. A call can come in from any number of sources. Not to mention call forwarding and all that stuff. Telcos would love to kill robo dialing, but they usually do it by requiring a certain percentage of calls to complete and last longer than 6 seconds. If you want to hurt them, answer and hangup immediately.
- russdill 9y ago
  Ah, that's why they don't say anything for 6 seconds.
ahmeni 9y ago
With number portability there is no solid "owner" of phone number blocks any more.
toast0 9y ago
There are a lot of legitimate reasons why a call from a number isn't coming from where you would be directing the call, so it's hard to fix it with a simple policy. What would be useful though is requiring something analogous to email received headers, combined with a real time method to report calls as spam/unwanted. If spam volume from an interconnecting carrier is too high, cut them off. Telco routing is a lot of twisty passages, but there are many fewer players than internet routing, so it should be easier to get bad apples off the network, as long as there is desire and some users are willing to provide feedback on calls.
- posguy 9y ago
  Carriers already do this FYI, but it only gets you so far. Robocallers pay higher rates due to this, but they seem glad to pay.

sbov 9y ago

So this is what was happening... I have a "desirable" prefix and had been getting tons of calls from numbers with the same prefix - was wondering why the heck they would be calling me.

smarks 9y ago
Here's another article (really, radio transcript) on this phenomenon: http://www.npr.org/2017/07/31/540515367/familiar-looking-numbers-are-the-latest-twist-in-robocalls http://www.npr.org/2017/07/31/540515367/familiar-looking-num... One thing that this doesn't mention, but which I heard somewhere, is don't call that number back and ask "Why did you call me?" In case it isn't obvious, the caller IDs are spoofed using random numbers, and the person who has the number listed doesn't know their number is being used this way. One amusing anecdote from the NPR piece is the person who received a call with a caller ID of ... their own phone number!