Facebook has been increasing there security day by day so that every user get secured from unauthorized user . If you notice some suspicious activity on your Facebook account such as wall post which you had never published or message which you had never send this means some one may have logging into your account. An authorized user can just inject some wall post or sending messages to your friends .Better to be on safe side by enabling some security settings .
Now let’s begin just log in to your account and go to Account Setting -> Security
Then consider the following security setting :-
1. Enable Secure browsing :-
Many unauthorized user creates pages which look like Facebook login page but they are fake pages without https . while login always see to URL if it’s secured or not. If page is not secured please don’t login Always Browse facebook on a secure connection (https).
2. Log-in Notification:-
To keep track on who is log-in, which enable log-in notification . whenever unauthorized user log-in to your account Facebook sends you text message (if you have registered your mobile) otherwise it will send you mail . facebook notify when your account is accessed from a computer or mobile device that you haven’t used before.
It’s Two-level security option which is the best security with almost no chances for unauthorized to log-in . In this whenever you log-in at unrecognized computer then Facebook will send you a security code on your mobile .
Active session is used to find where exactly your account was excesses . your current session will be on the top and on other computer below. If any Activity is unfamiliar then you can click on “End Activity” .