If somebody calls you, claiming to be from the IRS, using rude and threatening tactics, it is likely not legit.
There is a scam making the rounds, targeting South Florida taxpayers over the phone with threatening calls from supposed IRS agents. But, according to the Internal Revenue Service, there's a foolproof way to know you're dealing with the real thing.
You can call the IRS back at 1-800-829-1040. They can verify the name and badge number. Anybody calling from the IRS should be able to give you their badge number and their full name.
Also, a big clue: An IRS spokesman says agents will never use threats or be rude, which is what these callers are apparently doing, in an effort to get your financial information.