How to find out the real caller id?

Question

Asterisk

There is a possibility of Caller id spoofing during an incoming call, how can you calculate the fact of a spoofed number? If possible, I would like to know the real number of the caller

Answer 1

It depends on how (and for what) the substitution was made.
If the call is "forwarded", then the real number may be in the Diversion header.

Answer 2

exten => _X.,1,NoOp(num=${CALLERID(num)})
same => n,NoOp(name=${CALLERID(name)})
same => n,NoOp(ani=${CALLERID( ani)})
same => n,NoOp(rdnis=${CALLERID(rdnis)})
same => n,NoOp(all=${CALLERID(all)})
Something like this.