1) If you mean someone accessing your application & doing hanky panky with the front end, what I can think of is that you can use a stored procedure on certain screens that is called on the front end on certain operations you want to log. Then, you could provide that procedure with necessary identification parameters such as IPAddress, userName etc. & log these in a separate table.
2) If you are trying to log someone using SQL server you can use ConnectionProperty. However, I wonder if this would return you the application address if this is applied on a web application. This would help
http://msdn.microsoft.com/en-us/library/bb895240.aspx[
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