diff --git a/server/devicemanager.cpp b/server/devicemanager.cpp
index 94a38da..8ace3e3 100644
--- a/server/devicemanager.cpp
+++ b/server/devicemanager.cpp
@@ -321,6 +321,10 @@ Device* DeviceManager::originDevice(PacketBuffer *pktBuf)
     quint16 vlan;
     int idx = 0;
 
+    // Do we have any devices at all?
+    if (!deviceCount())
+       return NULL;
+
     // pktBuf will not have the correct dstMac populated, so use bcastMac
     // and search for device by IP
 
diff --git a/server/myservice.cpp b/server/myservice.cpp
index 2c5fc62..3d8531c 100644
--- a/server/myservice.cpp
+++ b/server/myservice.cpp
@@ -933,11 +933,18 @@ _invalid_port:
 quint64 getDeviceMacAddress(int portId, int streamId, int frameIndex)
 {
     MyService *service = drone->rpcService();
+    DeviceManager *devMgr = NULL;
     quint64 mac;
 
     if (!service)
         return 0;
 
+    if ((portId >= 0) && (portId < service->portInfo.size()))
+        devMgr = service->portInfo[portId]->deviceManager();
+
+    if (!devMgr || !devMgr->deviceCount())
+        return 0;
+
     service->portLock[portId]->lockForWrite();
     mac = service->portInfo[portId]->deviceMacAddress(streamId, frameIndex);
     service->portLock[portId]->unlock();
@@ -948,11 +955,18 @@ quint64 getDeviceMacAddress(int portId, int streamId, int frameIndex)
 quint64 getNeighborMacAddress(int portId, int streamId, int frameIndex)
 {
     MyService *service = drone->rpcService();
+    DeviceManager *devMgr = NULL;
     quint64 mac;
 
     if (!service)
         return 0;
 
+    if ((portId >= 0) && (portId < service->portInfo.size()))
+        devMgr = service->portInfo[portId]->deviceManager();
+
+    if (!devMgr || !devMgr->deviceCount())
+        return 0;
+
     service->portLock[portId]->lockForWrite();
     mac = service->portInfo[portId]->neighborMacAddress(streamId, frameIndex);
     service->portLock[portId]->unlock();