How to audit login

Many times we need to check users logged in our system for various reasons.
This reasons can be many but main requirement we need to know who logged in out system.
There are many ways in SQL Server for this and with introduction of newer versions
many new methods are available for this .

Lets see some of this.1
1.Using SSMS
Connect to server , go to properties.
Go to Security -> Login Auditing.
Select "Both failed and successful logins"

Now restart the server.
You can see the details in errorlog.



2.Using Profiler 
Connect to profiler.
Select events
"Audit Login"
"Audit Login Failed"
Start the trace.
You can see the detail in profiler trace.