@@ -68,7 +68,11 @@ func networkSize(mask net.IPMask) (int32, error) {

 // Wrapper around the iptables command

 func iptables(args ...string) error {

-	if err := exec.Command("/sbin/iptables", args...).Run(); err != nil {

+	path, err := exec.LookPath("iptables")

+	if err != nil {

+		return fmt.Errorf("command not found: iptables")

+	}

+	if err := exec.Command(path, args...).Run(); err != nil {

 		return fmt.Errorf("iptables failed: iptables %v", strings.Join(args, " "))

 	}

 	return nil

@@ -120,13 +124,13 @@ func (mapper *PortMapper) cleanup() error {

 func (mapper *PortMapper) setup() error {

 	if err := iptables("-t", "nat", "-N", "DOCKER"); err != nil {

-		return errors.New("Unable to setup port networking: Failed to create DOCKER chain")

+		return fmt.Errorf("Failed to create DOCKER chain: %s", err)

 	}

 	if err := iptables("-t", "nat", "-A", "PREROUTING", "-j", "DOCKER"); err != nil {

-		return errors.New("Unable to setup port networking: Failed to inject docker in PREROUTING chain")

+		return fmt.Errorf("Failed to inject docker in PREROUTING chain: %s", err)

 	}

 	if err := iptables("-t", "nat", "-A", "OUTPUT", "-j", "DOCKER"); err != nil {

-		return errors.New("Unable to setup port networking: Failed to inject docker in OUTPUT chain")

+		return fmt.Errorf("Failed to inject docker in OUTPUT chain: %s", err)

 	}

 	return nil

 }