diff --git a/gns3server/modules/dynamips/nodes/ethernet_switch.py b/gns3server/modules/dynamips/nodes/ethernet_switch.py
index fc74e09c..2f8f0d87 100644
--- a/gns3server/modules/dynamips/nodes/ethernet_switch.py
+++ b/gns3server/modules/dynamips/nodes/ethernet_switch.py
@@ -298,6 +298,9 @@ class EthernetSwitch(Device):
 
         nio = self._nios[port_number]
 
+        if not nio:
+            raise DynamipsError("Port {} is not connected".format(port_number))
+
         data_link_type = data_link_type.lower()
         if data_link_type.startswith("dlt_"):
             data_link_type = data_link_type[4:]
@@ -324,6 +327,10 @@ class EthernetSwitch(Device):
             raise DynamipsError("Port {} is not allocated".format(port_number))
 
         nio = self._nios[port_number]
+
+        if not nio:
+            raise DynamipsError("Port {} is not connected".format(port_number))
+
         yield from nio.unbind_filter("both")
         log.info('Ethernet switch "{name}" [{id}]: stopping packet capture on port {port}'.format(name=self._name,
                                                                                                   id=self._id,
diff --git a/gns3server/modules/dynamips/nodes/router.py b/gns3server/modules/dynamips/nodes/router.py
index 4efee4d0..0b0d6492 100644
--- a/gns3server/modules/dynamips/nodes/router.py
+++ b/gns3server/modules/dynamips/nodes/router.py
@@ -1303,6 +1303,10 @@ class Router(BaseVM):
 
         nio = adapter.get_nio(port_number)
 
+        if not nio:
+            raise DynamipsError("Port {slot_number}/{port_number} is not connected".format(slot_number=slot_number,
+                                                                                           port_number=port_number))
+
         if nio.input_filter[0] is not None and nio.output_filter[0] is not None:
             raise DynamipsError("Port {port_number} has already a filter applied on {adapter}".format(adapter=adapter,
                                                                                                       port_number=port_number))
@@ -1335,6 +1339,11 @@ class Router(BaseVM):
                                                                                                 port_number=port_number))
 
         nio = adapter.get_nio(port_number)
+
+        if not nio:
+            raise DynamipsError("Port {slot_number}/{port_number} is not connected".format(slot_number=slot_number,
+                                                                                           port_number=port_number))
+
         yield from nio.unbind_filter("both")
 
         log.info('Router "{name}" [{id}]: stopping packet capture on port {slot_number}/{port_number}'.format(name=self._name,
diff --git a/gns3server/modules/virtualbox/virtualbox_vm.py b/gns3server/modules/virtualbox/virtualbox_vm.py
index ddeb6089..546c2239 100644
--- a/gns3server/modules/virtualbox/virtualbox_vm.py
+++ b/gns3server/modules/virtualbox/virtualbox_vm.py
@@ -871,6 +871,10 @@ class VirtualBoxVM(BaseVM):
             raise VirtualBoxError("Sorry, packet capturing on a started VirtualBox VM is not supported.")
 
         nio = adapter.get_nio(0)
+
+        if not nio:
+            raise VirtualBoxError("Adapter {} is not connected".format(adapter_number))
+
         if nio.capturing:
             raise VirtualBoxError("Packet capture is already activated on adapter {adapter_number}".format(adapter_number=adapter_number))
 
@@ -893,6 +897,10 @@ class VirtualBoxVM(BaseVM):
                                                                                                             adapter_number=adapter_number))
 
         nio = adapter.get_nio(0)
+
+        if not nio:
+            raise VirtualBoxError("Adapter {} is not connected".format(adapter_number))
+
         nio.stopPacketCapture()
 
         log.info("VirtualBox VM '{name}' [{id}]: stopping packet capture on adapter {adapter_number}".format(name=self.name,