[asterisk-users] How to detect fake CallerID? (8xx?)

[Steve Edwards]

I have a 'time and attendance' application. Think janitorial or security 
kind of thing where an employee goes from location to location.

They're supposed to 'clock in' when they get to a site using a phone at 
that site to prove they're there.

Some employees have discovered 'fake caller ID' services can be used to 
say they're on site when they are not.

How can I detect a fake CallerID? The INVITE looks the same to me.

If I have the employees call an 8xx number, can I ask my SIP provider to 
include more headers to show the real ANI? What would that service be 
called?

-- 
Thanks in advance,
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Steve Edwards       sedwards at sedwards.com      Voice: +1-760-468-3867 PST
             https://www.linkedin.com/in/steve-edwards-4244281