diff --git a/config_example.yaml b/config_example.yaml
index 0a540ec..a430d90 100644
--- a/config_example.yaml
+++ b/config_example.yaml
@@ -15,3 +15,6 @@ nodes:
   saveinterval: 5
   aliases_enable: false
   aliases_path: webroot/aliases.json
+  vpn_addresses:
+  - da:25:d6:5c:97:6f
+  - da:62:f2:70:c8:8d
diff --git a/main.go b/main.go
index cfd0b4a..45769d1 100644
--- a/main.go
+++ b/main.go
@@ -32,10 +32,9 @@ func main() {
 	config = models.ConfigReadFile(configFile)
 
 	collectInterval := time.Second * time.Duration(config.Responedd.CollectInterval)
-	saveInterval := time.Second * time.Duration(config.Nodes.SaveInterval)
 
 	if config.Nodes.Enable {
-		go nodes.Saver(config.Nodes.NodesPath, config.Nodes.GraphsPath, saveInterval)
+		go nodes.Saver(config)
 	}
 	if config.Nodes.AliasesEnable {
 		// FIXME what does this do?
diff --git a/models/config.go b/models/config.go
index ff61593..e81ce96 100644
--- a/models/config.go
+++ b/models/config.go
@@ -24,12 +24,13 @@ type Config struct {
 		WebsocketAliases bool   `yaml:"websocketaliases"`
 	} `yaml:"webserver"`
 	Nodes struct {
-		Enable        bool   `yaml:"enable"`
-		NodesPath     string `yaml:"nodes_path"`
-		GraphsPath    string `yaml:"graphs_path"`
-		AliasesEnable bool   `yaml:"aliases_enable"`
-		AliasesPath   string `yaml:"aliases_path"`
-		SaveInterval  int    `yaml:"saveinterval"`
+		Enable        bool     `yaml:"enable"`
+		NodesPath     string   `yaml:"nodes_path"`
+		GraphsPath    string   `yaml:"graphs_path"`
+		AliasesEnable bool     `yaml:"aliases_enable"`
+		AliasesPath   string   `yaml:"aliases_path"`
+		SaveInterval  int      `yaml:"saveinterval"`
+		VpnAddresses  []string `yaml:"vpn_addresses"`
 	} `yaml:"nodes"`
 }
 
diff --git a/models/graph.go b/models/graph.go
index 16d6f33..67b1fb4 100644
--- a/models/graph.go
+++ b/models/graph.go
@@ -21,14 +21,21 @@ type GraphLink struct {
 }
 
 type GraphBuilder struct {
-	macToID map[string]string     // mapping from MAC address to node id
-	links   map[string]*GraphLink // mapping from $idA-$idB to existing link
+	macToID map[string]string      // mapping from MAC address to node id
+	links   map[string]*GraphLink  // mapping from $idA-$idB to existing link
+	vpn     map[string]interface{} // IDs/addresses of VPN servers
 }
 
-func (nodes *Nodes) BuildGraph() *Graph {
+func (nodes *Nodes) BuildGraph(vpnAddresses []string) *Graph {
 	builder := &GraphBuilder{
 		macToID: make(map[string]string),
 		links:   make(map[string]*GraphLink),
+		vpn:     make(map[string]interface{}),
+	}
+
+	// read VPN addresses into map
+	for _, address := range vpnAddresses {
+		builder.vpn[address] = nil
 	}
 
 	builder.readNodes(nodes.List)
@@ -44,6 +51,11 @@ func (builder *GraphBuilder) readNodes(nodes map[string]*Node) {
 		if neighbours := node.Neighbours; neighbours != nil {
 			for sourceAddress, _ := range neighbours.Batadv {
 				builder.macToID[sourceAddress] = sourceId
+
+				// is VPN address?
+				if _, found := builder.vpn[sourceAddress]; found {
+					builder.vpn[sourceId] = nil
+				}
 			}
 		}
 	}
@@ -73,6 +85,15 @@ func (builder *GraphBuilder) Links() []*GraphLink {
 	return links
 }
 
+func (builder *GraphBuilder) isVPN(ids ...string) bool {
+	for _, id := range ids {
+		if _, found := builder.vpn[id]; found {
+			return true
+		}
+	}
+	return false
+}
+
 func (builder *GraphBuilder) addLink(targetId string, sourceId string, linkTq int) {
 	// Order IDs to get generate the key
 	var key string
@@ -91,6 +112,7 @@ func (builder *GraphBuilder) addLink(targetId string, sourceId string, linkTq in
 		builder.links[key] = &GraphLink{
 			Source: sourceId,
 			Target: targetId,
+			VPN:    builder.isVPN(sourceId, targetId),
 			TQ:     tq,
 		}
 	} else {
diff --git a/models/nodes.go b/models/nodes.go
index 8616913..f042cf8 100644
--- a/models/nodes.go
+++ b/models/nodes.go
@@ -62,15 +62,19 @@ func (nodes *Nodes) Get(nodeID string) *Node {
 }
 
 // Saves the cached DB to json file periodically
-func (nodes *Nodes) Saver(nodesPath string, graphPath string, saveInterval time.Duration) {
-	c := time.Tick(saveInterval)
+func (nodes *Nodes) Saver(config *Config) {
+	c := time.Tick(time.Second * time.Duration(config.Nodes.SaveInterval))
 
 	for range c {
 		log.Println("saving", len(nodes.List), "nodes")
 		nodes.Timestamp = time.Now()
 		nodes.Lock()
-		save(nodes, nodesPath)
-		save(nodes.BuildGraph(), graphPath)
+		if path := config.Nodes.NodesPath; path != "" {
+			save(nodes, path)
+		}
+		if path := config.Nodes.GraphsPath; path != "" {
+			save(nodes.BuildGraph(config.Nodes.VpnAddresses), path)
+		}
 		nodes.Unlock()
 	}
 }