if !iptable.Exists(Nat, "PREROUTING", preroute...) && enable {
            if err := c.Prerouting(Append, preroute...); err != nil {
                return fmt.Errorf("failed to inject %s in PREROUTING chain: %s", c.Name, err)
            }
        } else if iptable.Exists(Nat, "PREROUTING", preroute...) && !enable {