[Tfug] OT - Telemarketing calls with fraudulent caller ID

[George Cohn]

Adrian wrote:

> Who ever is doing it 
> clearly knows exactly what they are doing, picking un-assigned numbering 
> ranges and having their PBX send out fraudulent CIDs in those ranges to try 
> and mask their true location. Unfortunately... until someone in a CO starts 
> going over the transfer records, it looks like this will continue unabated.
>

It's trivially easy to spoof caller ID in any current pbx.  In the big 
Nortel switches that I work on, there are user configurable tables that 
define how the caller ID is built, based on the area code, CO prefix, 
and DID or non-DID extension.

You can even build tables to make a number show another ID.  A 
legitimate use for this is in a medical office where you want all 
outgoing calls from physicians to show a central scheduling or operator 
number so return calls don't annoy the physicians.

It's even easier in voip systems like Asterisk where you can make the 
caller ID say anything for any extension just by adding a line of code 
to the configuration for a phone.

Because the phone system is so split up now, it's difficult to find 
anyone who takes an interest in tracking down a few dozen calls.

If you want to know more about how area codes and central office numbers 
are assigned, take a look at http://www.nanpa.com/ which is the central 
authority that oversees the North American Numbering Plan.

George Cohn