diff --git a/src/calibre/devices/smart_device_app/driver.py b/src/calibre/devices/smart_device_app/driver.py
index 4b749b21ca..33767d3e24 100644
--- a/src/calibre/devices/smart_device_app/driver.py
+++ b/src/calibre/devices/smart_device_app/driver.py
@@ -976,7 +976,7 @@ class SMART_DEVICE_APP(DeviceConfig, DevicePlugin):
             except:
                 message = _('Invalid port in options: %s')% \
                             self.settings().extra_customization[self.OPT_PORT_NUMBER]
-                self.debug(message)
+                self._debug(message)
                 self.listen_socket.close()
                 self.listen_socket = None
                 self.is_connected = False
@@ -984,7 +984,7 @@ class SMART_DEVICE_APP(DeviceConfig, DevicePlugin):
 
             port = self._attach_to_port(opt_port)
             if port == 0:
-                message = 'Failed to connect to port %d'%opt_port
+                message = _('Failed to connect to port %d. Try a different value.')%opt_port
                 self._debug(message)
                 self.listen_socket.close()
                 self.listen_socket = None
diff --git a/src/calibre/gui2/dialogs/smartdevice.py b/src/calibre/gui2/dialogs/smartdevice.py
index 1a8829323b..d8536a15cb 100644
--- a/src/calibre/gui2/dialogs/smartdevice.py
+++ b/src/calibre/gui2/dialogs/smartdevice.py
@@ -33,13 +33,12 @@ class SmartdeviceDialog(QDialog, Ui_Dialog):
             _('Check this box if you want calibre to use a fixed network '
               'port. Normally you will not need to do this. However, if '
               'your device consistently fails to connect to calibre, '
-              'try checking this box.') + '</p>')
+              'try checking this box and entering a number.') + '</p>')
 
         self.fixed_port.setToolTip('<p>' +
-            _('A port number must be a 4-digit integer less than 32,000. No '
-              'two network applications on the same computer can use '
-              'the same port number. If calibre says that it fails to connect '
-              'to the port, try a different number.') + '</p>')
+            _('Try 9090. If calibre says that it fails to connect '
+              'to the port, try another number. Yu can use any number between '
+              '8,000 and 32,000.') + '</p>')
 
         self.show_password.stateChanged[int].connect(self.toggle_password)
         self.use_fixed_port.stateChanged[int].connect(self.use_fixed_port_changed)
@@ -75,6 +74,23 @@ class SmartdeviceDialog(QDialog, Ui_Dialog):
                 Qt.Unchecked else QLineEdit.Normal)
 
     def accept(self):
+        port = unicode(self.fixed_port.text())
+        if not port:
+            error_dialog(self, _('Invalid port number'),
+                _('You must provide a port number.'), show=True)
+            return
+        try:
+            port = int(port)
+        except:
+            error_dialog(self, _('Invalid port number'),
+                _('The port must be a number between 8000 and 32000.'), show=True)
+            return
+
+        if port < 8000 or port > 32000:
+            error_dialog(self, _('Invalid port number'),
+                _('The port must be a number between 8000 and 32000.'), show=True)
+            return
+
         self.device_manager.set_option('smartdevice', 'password',
                                        unicode(self.password_box.text()))
         self.device_manager.set_option('smartdevice', 'autostart',