diff --git a/core/net/pom.xml b/core/net/pom.xml
index c075147..6518068 100644
--- a/core/net/pom.xml
+++ b/core/net/pom.xml
@@ -36,6 +36,12 @@
             <scope>test</scope>
         </dependency>
 
+	<dependency>
+	    <groupId>org.easymock</groupId>
+	    <artifactId>easymock</artifactId>
+	    <scope>test</scope>
+	</dependency>
+
         <!-- TODO Consider removing store dependency.
               Currently required for DistributedDeviceManagerTest. -->
         <dependency>
diff --git a/core/net/src/main/java/org/onlab/onos/net/host/impl/HostMonitor.java b/core/net/src/main/java/org/onlab/onos/net/host/impl/HostMonitor.java
index 6795cad..e6e348f 100644
--- a/core/net/src/main/java/org/onlab/onos/net/host/impl/HostMonitor.java
+++ b/core/net/src/main/java/org/onlab/onos/net/host/impl/HostMonitor.java
@@ -60,14 +60,15 @@
      *
      * @param deviceService device service used to find edge ports
      * @param packetService packet service used to send packets on the data plane
-     * @param hostService host service used to look up host information
+     * @param hostManager host manager used to look up host information and
+     * probe existing hosts
      */
     public HostMonitor(DeviceService deviceService, PacketService packetService,
-            HostManager hostService) {
+            HostManager hostManager) {
 
         this.deviceService = deviceService;
         this.packetService = packetService;
-        this.hostManager = hostService;
+        this.hostManager = hostManager;
 
         monitoredAddresses = Collections.newSetFromMap(
                 new ConcurrentHashMap<IpAddress, Boolean>());
diff --git a/core/net/src/test/java/org/onlab/onos/net/host/impl/HostMonitorTest.java b/core/net/src/test/java/org/onlab/onos/net/host/impl/HostMonitorTest.java
new file mode 100644
index 0000000..d766251
--- /dev/null
+++ b/core/net/src/test/java/org/onlab/onos/net/host/impl/HostMonitorTest.java
@@ -0,0 +1,220 @@
+package org.onlab.onos.net.host.impl;
+
+import static org.easymock.EasyMock.createMock;
+import static org.easymock.EasyMock.expect;
+import static org.easymock.EasyMock.expectLastCall;
+import static org.easymock.EasyMock.replay;
+import static org.easymock.EasyMock.verify;
+import static org.junit.Assert.assertTrue;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Set;
+
+import org.junit.Test;
+import org.onlab.onos.net.ConnectPoint;
+import org.onlab.onos.net.Device;
+import org.onlab.onos.net.DeviceId;
+import org.onlab.onos.net.Host;
+import org.onlab.onos.net.MastershipRole;
+import org.onlab.onos.net.Port;
+import org.onlab.onos.net.PortNumber;
+import org.onlab.onos.net.device.DeviceListener;
+import org.onlab.onos.net.device.DeviceService;
+import org.onlab.onos.net.flow.instructions.Instruction;
+import org.onlab.onos.net.flow.instructions.Instructions.OutputInstruction;
+import org.onlab.onos.net.host.HostProvider;
+import org.onlab.onos.net.host.PortAddresses;
+import org.onlab.onos.net.packet.OutboundPacket;
+import org.onlab.onos.net.packet.PacketProcessor;
+import org.onlab.onos.net.packet.PacketService;
+import org.onlab.onos.net.provider.ProviderId;
+import org.onlab.packet.ARP;
+import org.onlab.packet.Ethernet;
+import org.onlab.packet.IpAddress;
+import org.onlab.packet.IpPrefix;
+import org.onlab.packet.MacAddress;
+
+import com.google.common.collect.HashMultimap;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Multimap;
+
+public class HostMonitorTest {
+
+    private IpAddress targetIpAddress = IpAddress.valueOf("10.0.0.1");
+    private IpPrefix targetIpPrefix = IpPrefix.valueOf(targetIpAddress.toOctets());
+
+    private IpPrefix sourcePrefix = IpPrefix.valueOf("10.0.0.99/24");
+    private MacAddress sourceMac = MacAddress.valueOf(1L);
+
+    private HostMonitor hostMonitor;
+
+    @Test
+    public void testMonitorHostExists() throws Exception {
+        ProviderId id = new ProviderId("fake://", "id");
+
+        Host host = createMock(Host.class);
+        expect(host.providerId()).andReturn(id);
+        replay(host);
+
+        HostManager hostManager = createMock(HostManager.class);
+        expect(hostManager.getHostsByIp(targetIpPrefix))
+                .andReturn(Collections.singleton(host));
+        replay(hostManager);
+
+        HostProvider hostProvider = createMock(HostProvider.class);
+        expect(hostProvider.id()).andReturn(id).anyTimes();
+        hostProvider.triggerProbe(host);
+        expectLastCall().once();
+        replay(hostProvider);
+
+        hostMonitor = new HostMonitor(null, null, hostManager);
+
+        hostMonitor.registerHostProvider(hostProvider);
+        hostMonitor.addMonitoringFor(targetIpAddress);
+
+        hostMonitor.run(null);
+
+        verify(hostProvider);
+    }
+
+    @Test
+    public void testMonitorHostDoesNotExist() throws Exception {
+        HostManager hostManager = createMock(HostManager.class);
+
+        DeviceId devId = DeviceId.deviceId("fake");
+
+        Device device = createMock(Device.class);
+        expect(device.id()).andReturn(devId).anyTimes();
+        replay(device);
+
+        PortNumber portNum = PortNumber.portNumber(1L);
+
+        Port port = createMock(Port.class);
+        expect(port.number()).andReturn(portNum).anyTimes();
+        replay(port);
+
+        TestDeviceService deviceService = new TestDeviceService();
+        deviceService.addDevice(device, Collections.singleton(port));
+
+        ConnectPoint cp = new ConnectPoint(devId, portNum);
+        PortAddresses pa = new PortAddresses(cp, Collections.singleton(sourcePrefix),
+                sourceMac);
+
+        expect(hostManager.getHostsByIp(targetIpPrefix))
+                .andReturn(Collections.<Host>emptySet()).anyTimes();
+        expect(hostManager.getAddressBindingsForPort(cp))
+                .andReturn(pa).anyTimes();
+        replay(hostManager);
+
+        TestPacketService packetService = new TestPacketService();
+
+
+        // Run the test
+        hostMonitor = new HostMonitor(deviceService, packetService, hostManager);
+
+        hostMonitor.addMonitoringFor(targetIpAddress);
+        hostMonitor.run(null);
+
+
+        // Check that a packet was sent to our PacketService and that it has
+        // the properties we expect
+        assertTrue(packetService.packets.size() == 1);
+        OutboundPacket packet = packetService.packets.get(0);
+
+        // Check the output port is correct
+        assertTrue(packet.treatment().instructions().size() == 1);
+        Instruction instruction = packet.treatment().instructions().get(0);
+        assertTrue(instruction instanceof OutputInstruction);
+        OutputInstruction oi = (OutputInstruction) instruction;
+        assertTrue(oi.port().equals(portNum));
+
+        // Check the output packet is correct (well the important bits anyway)
+        Ethernet eth = new Ethernet();
+        eth.deserialize(packet.data().array(), 0, packet.data().array().length);
+        ARP arp = (ARP) eth.getPayload();
+        assertTrue(Arrays.equals(arp.getSenderProtocolAddress(), sourcePrefix.toOctets()));
+        assertTrue(Arrays.equals(arp.getSenderHardwareAddress(), sourceMac.toBytes()));
+        assertTrue(Arrays.equals(arp.getTargetProtocolAddress(), targetIpPrefix.toOctets()));
+    }
+
+    class TestPacketService implements PacketService {
+
+        List<OutboundPacket> packets = new ArrayList<>();
+
+        @Override
+        public void addProcessor(PacketProcessor processor, int priority) {
+        }
+
+        @Override
+        public void removeProcessor(PacketProcessor processor) {
+        }
+
+        @Override
+        public void emit(OutboundPacket packet) {
+            packets.add(packet);
+        }
+    }
+
+    class TestDeviceService implements DeviceService {
+
+        List<Device> devices = Lists.newArrayList();
+        Multimap<DeviceId, Port> devicePorts = HashMultimap.create();
+
+        void addDevice(Device device, Set<Port> ports) {
+            devices.add(device);
+            for (Port p : ports) {
+                devicePorts.put(device.id(), p);
+            }
+        }
+
+        @Override
+        public int getDeviceCount() {
+            return 0;
+        }
+
+        @Override
+        public Iterable<Device> getDevices() {
+            return devices;
+        }
+
+        @Override
+        public Device getDevice(DeviceId deviceId) {
+            return null;
+        }
+
+        @Override
+        public MastershipRole getRole(DeviceId deviceId) {
+            return null;
+        }
+
+        @Override
+        public List<Port> getPorts(DeviceId deviceId) {
+            List<Port> ports = Lists.newArrayList();
+            for (Port p : devicePorts.get(deviceId)) {
+                ports.add(p);
+            }
+            return ports;
+        }
+
+        @Override
+        public Port getPort(DeviceId deviceId, PortNumber portNumber) {
+            return null;
+        }
+
+        @Override
+        public boolean isAvailable(DeviceId deviceId) {
+            return false;
+        }
+
+        @Override
+        public void addListener(DeviceListener listener) {
+        }
+
+        @Override
+        public void removeListener(DeviceListener listener) {
+        }
+    }
+}
diff --git a/pom.xml b/pom.xml
index 665d1b0..9d7edfe 100644
--- a/pom.xml
+++ b/pom.xml
@@ -122,6 +122,12 @@
                 <version>1.9.13</version>
             </dependency>
 
+	    <dependency>
+	        <groupId>org.easymock</groupId>
+	        <artifactId>easymock</artifactId>
+	        <version>3.2</version>
+	        <scope>test</scope>
+	    </dependency>
 
             <!-- Web related -->
             <dependency>