Overwrite record by last iteration in Datatable

protected void Page_Load(object sender, EventArgs e)
        {
            SqlDataAdapter da = new SqlDataAdapter("SELECT PS, PS_IP_ADDRESS FROM m_police_station where STATE_CD=21 and PS_IP_ADDRESS is not Null and LANG_CD=99", con);
            DataSet ds = new DataSet();
            da.Fill(ds);

            List<string> strIP = new List<string>();    
            foreach(DataRow row in ds.Tables[0].Rows)
            {
                strIP.Add(row["PS_IP_ADDRESS"].ToString());
            }
         
            DataTable dt = ds.Tables[0];
            dt.Columns.Add("Status", typeof(string));
             
            foreach (DataRow dr in dt.Rows)
            {               
                foreach (string s in strIP)
                {
                    Ping p = new Ping();
                    PingReply r;
                                                //   String str = "10.0.0.0"; 
                    r = p.Send(s);
                    Response.Buffer = false;

                    if (r.Status == IPStatus.Success)
                    {
                        dr["Status"] = "Y";     //   Response.Write("Success \n");
                    }
                    else
                    {
                          dr["Status"] = "N";  //  Response.Write("fail");
                    }
                }

                Grid_Online_offline.DataSource = dt;
                Grid_Online_offline.DataBind();

            }

        }