The IP PIN (Identity Protection PIN) is a six-digit number issued to you by the IRS. The IRS will issue you a new number every year. They will only send you that six-digit number via the U.S. Postal mail, and they will send it to the mailing address you listed on your 2016 return. Until you get that IP PIN in the mail, you will not be able to e-file your return.
The IP PIN is mailed out each year in late December and early January. They don't give specific dates. So if you've not received your IP PIN by Jan 31st, you can contact the IRS directly at 1-800-829-1040. Expect long hold times on the phone this time of year.
I am dealing with this personally again for the 4th year in a row. I did not recieve my ipin in the mail. You can go to the irs website and request that they resend as long as you can prove you are you by verifying a open account loan/credit in your name and using a cellphone that is registered to you. They will then send it to you. 800-908-4490 is the department that deals with identity theft. But that number doesn't help only because there is no one there to answer the phone. Good luck. You'll need it.
S/n I did receive it last year and was able to efile but still had to go through the verification process that took an additional nine weeks followed by two weeks of calling and finally a representative requested that they (identity theft department) release it. And that is if they get it right the first time. The year before last I had to wait out a nine week waiting period three seperate times because it was not done correctly. Its been a joyful time.