Take the 2-minute tour ×
Information Security Stack Exchange is a question and answer site for Information security professionals. It's 100% free, no registration required.

This question already has an answer here:

I recently logged in to my Facebook from other PC and got notice. Please login from the PC you previously logged in.

I want to know what information Facebook uses to determine this change? I changed my ip to previous PC IP and got same thing again.

Then i tried to make my UserAgent same as previous PC. But again Same. This makes me curious what info is being used here to determine this change.

share|improve this question

marked as duplicate by Adnan, Polynomial, NULLZ, symcbean, TildalWave Jul 5 '13 at 11:24

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

    
@D3C4FF my question is specific about Facebook. And i have already tried DNS/IP/UserAgent still same message. –  BigSack Jul 5 '13 at 7:05
    
Agreed with @D3C4FF. Your question has already been answered there. Voted to close. –  Adnan Jul 5 '13 at 7:48
    
@Adnan , if you feel same then go for it. Thank you –  BigSack Jul 5 '13 at 7:50
    
They are called cookies. This should never have been asked. –  jrwren Jul 29 '13 at 18:18

1 Answer 1

The main method are probably cookies. Facebook will save a small textfile on your computer. Everytime you go to Facebook again it tries to read this file. This way it recognizes when your last login was and probably some other data. At the moment my browser has 13 cookies which come from Facebook.

So if Facebook can't read your cookies it thinks that the browser is new and sends you the message. If you delete the Facebook cookies in your existing browser and visit Facebook you'll also get the message.

share|improve this answer
    
Thanks! I will try to import cookies from my existing browser. –  BigSack Jul 5 '13 at 7:15

Not the answer you're looking for? Browse other questions tagged or ask your own question.