@@ -5,9 +5,10 @@ package nat

 import (

 	"fmt"

-	"github.com/dotcloud/docker/utils"

 	"strconv"

 	"strings"

+

+	"github.com/dotcloud/docker/utils"

 )

 const (

@@ -72,6 +73,15 @@ func SplitProtoPort(rawPort string) (string, string) {

 	return parts[1], parts[0]

 }

+func validateProto(proto string) bool {

+	for _, availableProto := range []string{"tcp", "udp"} {

+		if availableProto == proto {

+			return true

+		}

+	}

+	return false

+}

+

 // We will receive port specs in the format of ip:public:private/proto and these need to be

 // parsed in the internal types

 func ParsePortSpecs(ports []string) (map[Port]struct{}, map[Port][]PortBinding, error) {

@@ -113,6 +123,9 @@ func ParsePortSpecs(ports []string) (map[Port]struct{}, map[Port][]PortBinding,

 		if _, err := strconv.ParseUint(hostPort, 10, 16); hostPort != "" && err != nil {

 			return nil, nil, fmt.Errorf("Invalid hostPort: %s", hostPort)

 		}

+		if !validateProto(proto) {

+			return nil, nil, fmt.Errorf("Invalid proto: %s", proto)

+		}

 		port := NewPort(proto, containerPort)

 		if _, exists := exposedPorts[port]; !exists {