diff --git a/container.go b/container.go
index 777c057f67..48661a3098 100644
--- a/container.go
+++ b/container.go
@@ -202,14 +202,14 @@ func ParseRun(args []string, capabilities *Capabilities) (*Config, *HostConfig,
 	return config, hostConfig, cmd, nil
 }
 
-type portMapping map[string]string
+type PortMapping map[string]string
 
 type NetworkSettings struct {
 	IPAddress   string
 	IPPrefixLen int
 	Gateway     string
 	Bridge      string
-	PortMapping map[string]portMapping
+	PortMapping map[string]PortMapping
 }
 
 // String returns a human-readable description of the port mapping defined in the settings
@@ -693,9 +693,9 @@ func (container *Container) allocateNetwork() error {
 	if err != nil {
 		return err
 	}
-	container.NetworkSettings.PortMapping = make(map[string]portMapping)
-	container.NetworkSettings.PortMapping["Tcp"] = make(portMapping)
-	container.NetworkSettings.PortMapping["Udp"] = make(portMapping)
+	container.NetworkSettings.PortMapping = make(map[string]PortMapping)
+	container.NetworkSettings.PortMapping["Tcp"] = make(PortMapping)
+	container.NetworkSettings.PortMapping["Udp"] = make(PortMapping)
 	for _, spec := range container.Config.PortSpecs {
 		nat, err := iface.AllocatePort(spec)
 		if err != nil {