Re: Spoofing ?
Making spoofing impossible is the one and only real cure. It won't ever happen - telcos would lose all those telemarketing customers.
Not necessarily - if you're a legitimate company you can (or could once), at least in the UK, arrange for a presentation number to appear as your CLI. There were proper checks by the telco that the number you're presenting is one you're allowed to use. I know that if you've got a DDI block you can spoof any number within that range - the network will just verify that it is one you're allowed to use and will pass it on. Back in the day, it would even present a number to a digital line as 0345636X150 which is its way of telling you that BT would vouch for the digits preceding the X. It was up to your software to remove the X if you wanted it to.
(All of this may still be true, but it's 20 years since I was writing software to deal with it and did all sorts of tests to see what I could present as an outgoing number.)
Biting the hand that feeds IT
