diff --git a/server/server.py b/server/server.py
index 7404594..12a0f3c 100755
--- a/server/server.py
+++ b/server/server.py
@@ -69,6 +69,14 @@ class WebSockets(object):
     for target in targets:
       target.send(msgstr)
 
+  def BroadcastTargets(self):
+    self.Broadcast(self.masters, {
+      'type': 'targets',
+      'data': {
+        'targets': list(self.targets.keys()),
+      },
+    })
+
 
 class BaseWSHandler(websocket.WebSocket):
   def opened(self, image_types):
@@ -92,6 +100,7 @@ def GetSlaveWSHandler(image_types, websockets):
       websockets.slaves.remove(self)
       if self._hostname:
         del websockets.targets[self._hostname]
+        websockets.BroadcastTargets()
 
     def received_message(self, msg):
       parsed = json.loads(str(msg))
@@ -108,6 +117,7 @@ def GetSlaveWSHandler(image_types, websockets):
         if 'hostname' in parsed['data']:
           self._hostname = parsed['data']['hostname']
           websockets.targets[self._hostname] = self
+          websockets.BroadcastTargets()
 
   return SlaveWSHandler
 
@@ -117,6 +127,12 @@ def GetMasterWSHandler(image_types, websockets):
     def opened(self):
       super().opened(image_types)
       websockets.masters.add(self)
+      self.send(json.dumps({
+        'type': 'targets',
+        'data': {
+          'targets': list(websockets.targets.keys()),
+        },
+      }))
 
     def closed(self, code, reason=None):
       websockets.masters.remove(self)
diff --git a/server/static/control.css b/server/static/control.css
index 8cd57cf..24c5af8 100644
--- a/server/static/control.css
+++ b/server/static/control.css
@@ -35,13 +35,17 @@ header {
   padding: 2px;
 }
 
-hostname, lastSeen, uptime, timestamp, volumeID, reboot {
+hostname, lastReport, uptime, timestamp, volumeID, reboot {
   font-family: "droid-sans-mono";
   display: table-cell;
   padding: 2px;
   text-align: right;
 }
 
+instanceSection.live hostname {
+  color: #3299bb;
+}
+
 volumeID {
   cursor: pointer;
 }
diff --git a/server/static/control.js b/server/static/control.js
index 4d1ee68..38cb5e0 100644
--- a/server/static/control.js
+++ b/server/static/control.js
@@ -25,6 +25,8 @@ ImageController.prototype.onMessage_ = function(msg) {
       return this.onImageTypes_(msg['data']);
     case 'report':
       return this.onReport_(msg['data']);
+    case 'targets':
+      return this.onTargets_(msg['data']);
   }
 };
 
@@ -50,7 +52,7 @@ ImageController.prototype.addImageType_ = function(type) {
   this.insertSorted_(this.container_, value.section, type);
   let headers = this.createNode_(value.section, 'headers');
   this.createNode_(headers, 'header', 'Hostname');
-  this.createNode_(headers, 'header', 'Last seen');
+  this.createNode_(headers, 'header', 'Last report');
   this.createNode_(headers, 'header', 'Uptime');
   this.createNode_(headers, 'header', 'Current image');
   this.createNode_(headers, 'header', 'Current volume ID');
@@ -70,8 +72,8 @@ ImageController.prototype.onReport_ = function(msg) {
     this.addInstance_(type, msg['hostname']);
   }
   let instance = type.instances.get(msg['hostname']);
-  instance.last_report = Math.floor(Date.now() / 1000);
-  instance.last_seen.innerText = this.formatSeconds_(0);
+  instance.last_report_timestamp = Math.floor(Date.now() / 1000);
+  instance.last_report.innerText = this.formatSeconds_(0);
   instance.uptime.innerText = this.formatSeconds_(msg['uptime_seconds']);
   instance.timestamp.innerText = msg['timestamp'];
   let volume_id_len = localStorage.getItem('volume_id_len') || Number.POSITIVE_INFINITY;
@@ -86,7 +88,7 @@ ImageController.prototype.addInstance_ = function(type, hostname) {
   };
   this.insertSorted_(type.section, value.section, hostname);
   this.createNode_(value.section, 'hostname', hostname);
-  value.last_seen = this.createNode_(value.section, 'lastSeen');
+  value.last_report = this.createNode_(value.section, 'lastReport');
   value.uptime = this.createNode_(value.section, 'uptime');
   value.timestamp = this.createNode_(value.section, 'timestamp');
   value.volume_id = this.createNode_(value.section, 'volumeID');
@@ -104,12 +106,25 @@ ImageController.prototype.addInstance_ = function(type, hostname) {
   type.instances.set(hostname, value);
 };
 
+ImageController.prototype.onTargets_ = function(msg) {
+  let targets = new Set(msg['targets']);
+  for (let [type, type_value] of this.image_types_) {
+    for (let [instance, instance_value] of type_value.instances) {
+      if (targets.has(instance)) {
+        instance_value.section.classList.add('live');
+      } else {
+        instance_value.section.classList.remove('live');
+      }
+    }
+  }
+};
+
 ImageController.prototype.onTick_ = function() {
   let now = Math.floor(Date.now() / 1000);
-  for (let [type, type_section] of this.image_types_) {
-    for (let [instance, instance_section] of type_section.instances) {
-      instance_section.last_seen.innerText =
-          this.formatSeconds_(now - instance_section.last_report);
+  for (let [type, type_value] of this.image_types_) {
+    for (let [instance, instance_value] of type_value.instances) {
+      instance_value.last_report.innerText =
+          this.formatSeconds_(now - instance_value.last_report_timestamp);
     }
   }
 };