diff --git a/cmd/demo/demo.go b/cmd/demo/demo.go
index 5a35cd2..ec4064f 100644
--- a/cmd/demo/demo.go
+++ b/cmd/demo/demo.go
@@ -10,12 +10,16 @@ import (
 	adb "github.com/zach-klippenstein/goadb"
 )
 
-var port = flag.Int("p", goadb.AdbPort, "")
+var port = flag.Int("p", adb.AdbPort, "")
 
 func main() {
 	flag.Parse()
 
-	client := adb.NewHostClientPort(*port)
+	client, err := adb.NewHostClientPort(*port)
+	if err != nil {
+		log.Fatal(err)
+	}
+
 	fmt.Println("Starting server…")
 	client.StartServer()
 
@@ -100,6 +104,14 @@ func PrintDeviceInfo(device *adb.DeviceClient) error {
 		}
 	}
 
+	fmt.Println("\tnon-existent file:")
+	stat, err = device.Stat("/supercalifragilisticexpialidocious")
+	if err != nil {
+		fmt.Println("\terror:", err)
+	} else {
+		fmt.Printf("\tstat: %+v\n", stat)
+	}
+
 	fmt.Print("\tload avg: ")
 	loadavgReader, err := device.OpenRead("/proc/loadavg")
 	if err != nil {
diff --git a/device_client.go b/device_client.go
index dcffa42..8a3d503 100644
--- a/device_client.go
+++ b/device_client.go
@@ -10,7 +10,7 @@ import (
 
 // DeviceClient communicates with a specific Android device.
 type DeviceClient struct {
-	dialer     nilSafeDialer
+	dialer     wire.Dialer
 	descriptor *DeviceDescriptor
 }
 
diff --git a/device_client_test.go b/device_client_test.go
index 37131d3..762d6d7 100644
--- a/device_client_test.go
+++ b/device_client_test.go
@@ -12,7 +12,7 @@ func TestGetAttribute(t *testing.T) {
 		Status:   wire.StatusSuccess,
 		Messages: []string{"value"},
 	}
-	client := &DeviceClient{nilSafeDialer{s}, deviceWithSerial("serial")}
+	client := &DeviceClient{s, deviceWithSerial("serial")}
 
 	v, err := client.getAttribute("attr")
 	assert.Equal(t, "host-serial:serial:attr", s.Requests[0])
@@ -25,7 +25,7 @@ func TestRunCommandNoArgs(t *testing.T) {
 		Status:   wire.StatusSuccess,
 		Messages: []string{"output"},
 	}
-	client := &DeviceClient{nilSafeDialer{s}, anyDevice()}
+	client := &DeviceClient{s, anyDevice()}
 
 	v, err := client.RunCommand("cmd")
 	assert.Equal(t, "host:transport-any", s.Requests[0])
diff --git a/host_client.go b/host_client.go
index 8497845..18d80ba 100644
--- a/host_client.go
+++ b/host_client.go
@@ -2,6 +2,7 @@
 package goadb
 
 import (
+	"errors"
 	"os/exec"
 	"strconv"
 
@@ -26,19 +27,22 @@ See list of services at https://android.googlesource.com/platform/system/core/+/
 */
 // TODO(z): Finish implementing host services.
 type HostClient struct {
-	dialer nilSafeDialer
+	dialer wire.Dialer
 }
 
-func NewHostClient() *HostClient {
-	return NewHostClientDialer(nil)
+func NewHostClient() (*HostClient, error) {
+	return NewHostClientPort(AdbPort)
 }
 
-func NewHostClientPort(port int) *HostClient {
-	return NewHostClientDialer(wire.NewDialer("", port))
+func NewHostClientPort(port int) (*HostClient, error) {
+	return NewHostClientDialer(wire.NewDialer("localhost", port))
 }
 
-func NewHostClientDialer(d wire.Dialer) *HostClient {
-	return &HostClient{nilSafeDialer{d}}
+func NewHostClientDialer(d wire.Dialer) (*HostClient, error) {
+	if d == nil {
+		return nil, errors.New("dialer cannot be nil.")
+	}
+	return &HostClient{d}, nil
 }
 
 // GetServerVersion asks the ADB server for its internal version number.
diff --git a/host_client_test.go b/host_client_test.go
index 7638f85..c50e63d 100644
--- a/host_client_test.go
+++ b/host_client_test.go
@@ -14,7 +14,8 @@ func TestGetServerVersion(t *testing.T) {
 		Status:   wire.StatusSuccess,
 		Messages: []string{"000a"},
 	}
-	client := NewHostClientDialer(s)
+	client, err := NewHostClientDialer(s)
+	assert.NoError(t, err)
 
 	v, err := client.GetServerVersion()
 	assert.Equal(t, "host:version", s.Requests[0])
diff --git a/wire/dialer.go b/wire/dialer.go
index 57b0e23..6473ead 100644
--- a/wire/dialer.go
+++ b/wire/dialer.go
@@ -1,6 +1,7 @@
 package wire
 
 import (
+	"errors"
 	"fmt"
 	"net"
 	"runtime"
@@ -27,10 +28,15 @@ func NewDialer(host string, port int) Dialer {
 func (d *netDialer) Dial() (*Conn, error) {
 	host := d.Host
 	if host == "" {
-		host = "localhost"
+		return nil, errors.New("Must specify adb hostname (cannot be empty).")
 	}
 
-	netConn, err := net.Dial("tcp", fmt.Sprintf("%s:%d", host, d.Port))
+	port := d.Port
+	if port == 0 {
+		return nil, errors.New("Must specify port (cannot be 0).")
+	}
+
+	netConn, err := net.Dial("tcp", fmt.Sprintf("%s:%d", host, port))
 	if err != nil {
 		return nil, err
 	}