News for hackers. Stuff that matters.

A comment on Ask HN: Should you reply STOP to unwanted texts?. Parent comment

Re:Ask HN: Should you reply STOP to unwanted texts? by fy20 on Tuesday October 01, 2024 @09:24AM (#41708064)
You can verify a phone number is real and active without needing them to reply, or without someone even receiving a notification.

1) SMS supports receipt functionality, which means the sender can be notified when a message is delivered to a handset. This happens at the carrier level, so you can't turn it off.

2) SMS supports 'silent' messages which are a different message class that is not shown to users.

[ Parent | on HN ]
Re:Ask HN: Should you reply STOP to unwanted texts? by toast0 on Tuesday October 01, 2024 @12:01PM (#41710182)
Receipts are unreliable. Carriers and aggregators regularly filter or fake them.

Receiving a receipt is not a real indication of delivery, and absence of receipt is not a real indication of absence of delivery.

[ Parent | on HN ]
Re:Ask HN: Should you reply STOP to unwanted texts? by kube-system on Tuesday October 01, 2024 @10:37AM (#41709030)
True, however, "delivered to a device" and "there's someone reading and replying at the other end" are two different confidence levels of "active".

You could, for instance, be texting an unattended device.

[ Parent | on HN ]