How to get a client system IP address

HI,
please use the below function to get the client ip address.
private string IppAddress()
    {

        string strIpAddress;

        strIpAddress = Request.ServerVariables["HTTP_X_FORWARDED_FOR"];

        if (strIpAddress == null)

            strIpAddress = Request.ServerVariables["REMOTE_ADDR"];

        return strIpAddress;

    }