Re: Voicemail without a call

Frank Slootweg <this@ddress.is.invalid> wrote:

Jim Jackson <jj@franjam.org.uk> wrote:

On 2025-03-28, Frank Slootweg <this@ddress.is.invalid> wrote:

VanguardLH <V@nguard.lh> wrote:
[...]

However, I tend to distrust texts since most do not identify the caller.
I see "24530" as the caller.  What the fuck is that?  Personal callers
usually show their phone number, so there's a match up to my Contacts
list, but stupidly all those 2FA codes sent by a web site do NOT
identify the web site sent them, and 2FA mining is a problem.  Maybe I
just did something, like renew a prescription at my pharmacy's web site,
so a text from some garbage numbered sender that says it is from my
pharmacy that arrives within 2 minutes of my action at their web site
provides context for the text.  However, context is not the same as
identification. 

>
  Hmm? Strange! Not that I get that many SMS messages for 2SV or
information, but the ones I get, always have a 'name' - for example an
airline - or a telephone number.
>
  Perhaps this no-name problem is US-specific? (I am in The
Netherlands.)

 
My experience is same as yours - I always get a number - or if contacts
the name). I'm in UK.

 
  But, as implied, I also get names for some/most organizations which
are not in my Contacts on the phone. For example an airline (KLM) and
many, many others.
 
  Of course many of those may be in *a* contact list (mainly in the
(Mozilla Thunderbird) address book on my laptop), but in not the one on
my phone. Anyway, the other contact list is a email contact list,
without phone numbers.
 
  So these senders have ways to send their name instead of their number.
 

  But indeed, also for our pharmacy, it's a number, but it's always the
same number, so no problem. If I could be bothered, I could put the
number in my Contacts list. Problem solved.
>
[...]

My Contacts records let me add phone numbers, but not Sender IDs.  A
Sender ID may be a phone number (or just look like a phone number, but
really is not a phone number), but it really is just a numeric string
(some countries allow alphabetic characters in Sender IDs). 

When I look in my Contacts records, there is no field for recording a
contact's Sender ID, only for phone numbers.  Besides having non-legit
alphabetic characters (in the USA, and some other countries) in the
Sender ID, the Sender ID can be spoofed.  Sender IDs are rarely
registered, but then you don't have access to do a lookup in some
non-centralized registry.

What you say is a phone number displayed for an SMS text is actually the
Sender ID.  Sometimes the Sender ID looks like a phone number whether it
is or is not a phone number.  Sometimes it is just a 1- to 15-character
numeric string (or 1- to 11-character alphanumeric string in some
countries).

https://thesmsworks.co.uk/blog/sms-sender-id/

The Sender ID in texts is as [un]trustworthy as is the From header in
e-mails.  The sender gets to specify their Sender ID just like they get
to specify their From header.  Spammers and scammers love it is so easy
to spoof those headers.