diff --git a/crawl/Crawl.cs b/crawl/Crawl.cs
index 231b177..78c6f2d 100644
--- a/crawl/Crawl.cs
+++ b/crawl/Crawl.cs
@@ -98,19 +98,22 @@ namespace ln.skyscanner.crawl
 
             DateTime dateTime = DateTime.Now;
 
-            while (servicesToCheck.Count > 0)
-                RunServiceCheck(servicesToCheck[0]);
+            try
+            {
 
-            //if (CrawledHost.FirstSeen.Equals(DateTime.MinValue))
-            //    CrawledHost.FirstSeen = DateTime.Now;
+                while (servicesToCheck.Count > 0)
+                    RunServiceCheck(servicesToCheck[0]);
 
-            ////CrawledHost.LastSeen = DateTime.Now;
+                Host.LastCheckTime = DateTime.Now - dateTime;
+                Host.LastCheck = dateTime;
+                Host.NextCheck = dateTime + TimeSpan.FromHours(1);
+            } catch (Exception e)
+            {
+                Logging.Log(LogLevel.ERROR, "Crawl.RunJob(): Caught exception: {0}",e);
+                Logging.Log(e);
+            }
 
-            Host.LastCheckTime = DateTime.Now - dateTime;
-            Host.LastCheck = dateTime;
-            Host.NextCheck = dateTime + TimeSpan.FromHours(1);
-
-            bool updated = Crawler.CrawledHosts.Update( Host );
+            bool updated = Crawler.CrawledHosts.Upsert( Host );
 
             setState("Updating global network");
             SkyScanner.Instance.Entities.GlobalNetwork.EnqueueUpdate(Host);
diff --git a/entities/GlobalNetwork.cs b/entities/GlobalNetwork.cs
index e9ca68f..b413128 100644
--- a/entities/GlobalNetwork.cs
+++ b/entities/GlobalNetwork.cs
@@ -65,14 +65,22 @@ namespace ln.skyscanner.entities
         public IEnumerable<Node> FindHostsInSubnet(CIDR network)
         {
             IntfIP[] intfIPs = SkyEntities.intfIPCollection.Select((ip) => ip.IP.In(network)).ToArray();
-            NetworkInterface[] networkInterfaces = intfIPs.Select((iip) => iip.NetworkInterface).Distinct().ToArray();
-            Node[] nodes = SkyEntities.nodeCollection.Select(networkInterfaces.Select((ni) => (ODBValue)ni.NodeID).Distinct()).ToArray();
+            NetworkInterface[] networkInterfaces = intfIPs.Select((iip) => iip.NetworkInterface).Where((i)=>i!=null).Distinct().ToArray();
+            Node[] nodes = SkyEntities.nodeCollection.Select(networkInterfaces.Select((ni) => new ODBGuid(ni.NodeID))).ToArray();
             return nodes;
         }
 
         public IEnumerable<Node> FindNeighbors(Node node)
         {
-            return node.IPAdresses.SelectMany((ip) => Timing.Meassure("FindHostsInSubnet", () => FindHostsInSubnet(ip)).Distinct().ToArray());
+            HashSet<Node> nodes = new HashSet<Node>();
+            foreach (Node neighbor in node.IPAdresses.SelectMany(
+            (ip) => Timing.Meassure("FindHostsInSubnet", () => 
+                FindHostsInSubnet(ip)
+                )
+                ))
+                nodes.Add(neighbor);
+
+            return nodes;
         }
 
         public Node FindNodeByIP(IEnumerable<CIDR> ips)
@@ -114,16 +122,23 @@ namespace ln.skyscanner.entities
             }
             while (true)
             {
-                CrawledHost crawledHost = null;
-                lock (updateQueue)
+                try
                 {
-                    if (updateQueue.Count > 0)
-                        crawledHost = updateQueue.Dequeue();
-                    else
-                        break;
-                }
+                    CrawledHost crawledHost = null;
+                    lock (updateQueue)
+                    {
+                        if (updateQueue.Count > 0)
+                            crawledHost = updateQueue.Dequeue();
+                        else
+                            break;
+                    }
 
-                Update(crawledHost);
+                    Update(crawledHost);
+                } catch (Exception e)
+                {
+                    Logging.Log(LogLevel.ERROR, "GlobalNetwork.Update(): Caught Exception: {0}",e);
+                    Logging.Log(e);
+                }
             }
 
             //SkyScanner.Entities.DBGlobalNetwork.SavePersistent(SkyScanner.Entities.DBGlobalNetwork.Root);
@@ -142,8 +157,17 @@ namespace ln.skyscanner.entities
                 node = new Node(crawledHost.PrimaryIP);
                 node.Name = crawledHost.Name;
                 node.PrimaryMac = crawledHost.PrimaryHWAddr;
+
+                SkyEntities.nodeCollection.Insert(node);
             }
 
+            if (!crawledHost.PrimaryIP.Equals(node.PrimaryIP))
+            {
+                Logging.Log(LogLevel.INFO,"GlobalNetwork.Update(): will not update Node with unmatched PrimaryIP {0} != {1}",node.PrimaryIP, crawledHost.PrimaryIP);
+                return;
+            }
+
+
             foreach (String si in crawledHost.GetHint<string[]>("rfc1213.interfaces",new string[0]))
             {
                 String[] fields = si.Split(';');
@@ -178,7 +202,6 @@ namespace ln.skyscanner.entities
 
                     if (crawledIPs.Contains(ip))
                     {
-                        EnsureSubnet(ip.Network);
                     }
                     else
                     {
@@ -203,6 +226,11 @@ namespace ln.skyscanner.entities
             }
 
 
+            foreach (CIDR ip in node.IPAdresses)
+            {
+                EnsureSubnet(ip.Network);
+            }
+
             node.LastUpdate = DateTime.Now;
             SkyEntities.nodeCollection.Upsert(node);
         }
diff --git a/entities/Node.cs b/entities/Node.cs
index 5714cc5..25ba073 100644
--- a/entities/Node.cs
+++ b/entities/Node.cs
@@ -92,5 +92,15 @@ namespace ln.skyscanner.entities
             return GetInterface(intfName) != null;
         }
 
+        public override int GetHashCode()
+        {
+            return ID.GetHashCode();
+        }
+
+        public override bool Equals(object obj)
+        {
+            return (obj is Node) && (ID.Equals((obj as Node).ID));
+        }
+
     }
 }
diff --git a/http/NetworkApi.cs b/http/NetworkApi.cs
index 03d9bc4..af13c91 100644
--- a/http/NetworkApi.cs
+++ b/http/NetworkApi.cs
@@ -34,8 +34,8 @@ namespace ln.skyscanner.http
         [Callable]
         public Node[] GetNeighbors(string pid)
         {
-            Guid persistenceID = Guid.Parse(pid);
-            return GlobalNetwork.FindNeighbors(GlobalNetwork.GetNode(persistenceID)).ToArray();
+            Guid nodeID = Guid.Parse(pid);
+            return GlobalNetwork.FindNeighbors(GlobalNetwork.GetNode(nodeID)).ToArray();
         }
 
         [Callable]