Add flag to set the default ip ports are bound to

config.go

@@ -1,5 +1,9 @@
 package docker
 
+import (
+	"net"
+)
+
 type DaemonConfig struct {
 	Pidfile        string
 	GraphPath      string
@@ -9,4 +13,5 @@ type DaemonConfig struct {
 	Dns            []string
 	EnableIptables bool
 	BridgeIface    string
+	DefaultIp      net.IP
 }

docker/docker.go

@@ -7,6 +7,7 @@ import (
 	"github.com/dotcloud/docker/utils"
 	"io/ioutil"
 	"log"
+	"net"
 	"os"
 	"os/signal"
 	"strconv"
@@ -38,7 +39,10 @@ func main() {
 	flHosts := docker.ListOpts{fmt.Sprintf("unix://%s", docker.DEFAULTUNIXSOCKET)}
 	flag.Var(&flHosts, "H", "tcp://host:port to bind/connect to or unix://path/to/socket to use")
 	flEnableIptables := flag.Bool("iptables", true, "Disable iptables within docker")
+	flDefaultIp := flag.String("ip", "0.0.0.0", "Default ip address to use when binding a containers ports")
+
 	flag.Parse()
+
 	if *flVersion {
 		showVersion()
 		return
@@ -69,6 +73,8 @@ func main() {
 			dns = []string{*flDns}
 		}
 
+		ip := net.ParseIP(*flDefaultIp)
+
 		config := &docker.DaemonConfig{
 			Pidfile:        *pidfile,
 			GraphPath:      *flGraphPath,
@@ -78,6 +84,7 @@ func main() {
 			EnableIptables: *flEnableIptables,
 			BridgeIface:    bridge,
 			ProtoAddresses: flHosts,
+			DefaultIp:      ip,
 		}
 		if err := daemon(config); err != nil {
 			log.Fatal(err)

network.go

@@ -210,7 +210,8 @@ type PortMapper struct {
 	udpMapping map[int]*net.UDPAddr
 	udpProxies map[int]proxy.Proxy
 
-	iptables *iptables.Chain
+	iptables  *iptables.Chain
+	defaultIp net.IP
 }
 
 func (mapper *PortMapper) Map(port int, backendAddr net.Addr) error {
@@ -223,7 +224,7 @@ func (mapper *PortMapper) Map(port int, backendAddr net.Addr) error {
 			}
 		}
 		mapper.tcpMapping[port] = backendAddr.(*net.TCPAddr)
-		proxy, err := proxy.NewProxy(&net.TCPAddr{IP: net.IPv4(0, 0, 0, 0), Port: port}, backendAddr)
+		proxy, err := proxy.NewProxy(&net.TCPAddr{IP: mapper.defaultIp, Port: port}, backendAddr)
 		if err != nil {
 			mapper.Unmap(port, "tcp")
 			return err
@@ -239,7 +240,7 @@ func (mapper *PortMapper) Map(port int, backendAddr net.Addr) error {
 			}
 		}
 		mapper.udpMapping[port] = backendAddr.(*net.UDPAddr)
-		proxy, err := proxy.NewProxy(&net.UDPAddr{IP: net.IPv4(0, 0, 0, 0), Port: port}, backendAddr)
+		proxy, err := proxy.NewProxy(&net.UDPAddr{IP: mapper.defaultIp, Port: port}, backendAddr)
 		if err != nil {
 			mapper.Unmap(port, "udp")
 			return err
@@ -305,6 +306,7 @@ func newPortMapper(config *DaemonConfig) (*PortMapper, error) {
 		udpMapping: make(map[int]*net.UDPAddr),
 		udpProxies: make(map[int]proxy.Proxy),
 		iptables:   chain,
+		defaultIp:  config.DefaultIp,
 	}
 	return mapper, nil
 }