public string GetCountryByIp(string ip) 
{
    string country = string.Empty;
    SqlConnection cn = null;
    try
    {
        IPAddress address = null;
        if (!IPAddress.TryParse(ip, out address))
            throw new Exception("The string '" + ip + "' is not a valid IP address");
        string[] ipmask = ip.Split('.');
        double ipNumber = Convert.ToInt16(ipmask[0]) * 16777216d + Convert.ToInt16(ipmask[1]) * 65536 + Convert.ToInt16(ipmask[2]) * 256 + Convert.ToInt16(ipmask[3]);
        
        
        cn = new SqlConnection();
        cn.ConnectionString = ConfigurationManager.ConnectionStrings["..."].ConnectionString;
        cn.Open();
        SqlCommand cmd = new SqlCommand();
    
        cmd.CommandText = "getCountryByIp";
        cmd.CommandType = CommandType.StoredProcedure;
        cmd.Connection = cn;
        cmd.Parameters.Add(new SqlParameter("@ipx", ipNumber));
        SqlDataReader dr = cmd.ExecuteReader();
        while (dr.Read())
            country = dr["stato_completo"].ToString();
        dr.Close();
        dr.Dispose();
        cmd.Dispose();
        return country;  
    }
    catch (Exception ex)
    {
        throw ex;
    }
    finally
    {
        if (cn != null)
        {
            if(cn.State == ConnectionState.Open)
                cn.Close();
            cn.Dispose();
        }
    }  
}