diff --git a/core/net/src/main/java/org/onlab/onos/net/proxyarp/impl/ProxyArpManager.java b/core/net/src/main/java/org/onlab/onos/net/proxyarp/impl/ProxyArpManager.java
index 4933322..ac10384 100644
--- a/core/net/src/main/java/org/onlab/onos/net/proxyarp/impl/ProxyArpManager.java
+++ b/core/net/src/main/java/org/onlab/onos/net/proxyarp/impl/ProxyArpManager.java
@@ -55,6 +55,7 @@
     private static final String REQUEST_NULL = "Arp request cannot be null.";
     private static final String REQUEST_NOT_ARP = "Ethernet frame does not contain ARP request.";
     private static final String NOT_ARP_REQUEST = "ARP is not a request.";
+    private static final String NOT_ARP_REPLY = "ARP is not a reply.";
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     protected HostService hostService;
@@ -141,7 +142,7 @@
         checkArgument(eth.getEtherType() == Ethernet.TYPE_ARP,
                 REQUEST_NOT_ARP);
         ARP arp = (ARP) eth.getPayload();
-        checkArgument(arp.getOpCode() == ARP.OP_REPLY, NOT_ARP_REQUEST);
+        checkArgument(arp.getOpCode() == ARP.OP_REPLY, NOT_ARP_REPLY);
 
         Host h = hostService.getHost(HostId.hostId(eth.getDestinationMAC(),
                 VlanId.vlanId(eth.getVlanID())));
diff --git a/core/net/src/test/java/org/onlab/onos/net/proxyarp/impl/ProxyArpManagerTest.java b/core/net/src/test/java/org/onlab/onos/net/proxyarp/impl/ProxyArpManagerTest.java
new file mode 100644
index 0000000..ddd4827
--- /dev/null
+++ b/core/net/src/test/java/org/onlab/onos/net/proxyarp/impl/ProxyArpManagerTest.java
@@ -0,0 +1,442 @@
+package org.onlab.onos.net.proxyarp.impl;
+
+import static org.easymock.EasyMock.anyObject;
+import static org.easymock.EasyMock.createMock;
+import static org.easymock.EasyMock.expect;
+import static org.easymock.EasyMock.replay;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.onlab.onos.net.ConnectPoint;
+import org.onlab.onos.net.DefaultHost;
+import org.onlab.onos.net.Device;
+import org.onlab.onos.net.DeviceId;
+import org.onlab.onos.net.Host;
+import org.onlab.onos.net.HostId;
+import org.onlab.onos.net.HostLocation;
+import org.onlab.onos.net.Link;
+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.HostService;
+import org.onlab.onos.net.link.LinkListener;
+import org.onlab.onos.net.link.LinkService;
+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.IpPrefix;
+import org.onlab.packet.MacAddress;
+import org.onlab.packet.VlanId;
+
+import com.google.common.collect.Sets;
+
+/**
+ * Tests for the {@link ProxyArpManager} class.
+ */
+public class ProxyArpManagerTest {
+
+    private static final int NUM_DEVICES = 4;
+    private static final int NUM_PORTS_PER_DEVICE = 3;
+    private static final int NUM_FLOOD_PORTS = 4;
+
+    private static final IpPrefix IP1 = IpPrefix.valueOf("10.0.0.1/24");
+    private static final IpPrefix IP2 = IpPrefix.valueOf("10.0.0.2/24");
+
+    private static final ProviderId PID = new ProviderId("of", "foo");
+
+    private static final VlanId VLAN1 = VlanId.vlanId((short) 1);
+    private static final VlanId VLAN2 = VlanId.vlanId((short) 2);
+    private static final MacAddress MAC1 = MacAddress.valueOf("00:00:11:00:00:01");
+    private static final MacAddress MAC2 = MacAddress.valueOf("00:00:22:00:00:02");
+    private static final HostId HID1 = HostId.hostId(MAC1, VLAN1);
+    private static final HostId HID2 = HostId.hostId(MAC2, VLAN1);
+
+    private static final DeviceId DID1 = getDeviceId(1);
+    private static final DeviceId DID2 = getDeviceId(2);
+    private static final PortNumber P1 = PortNumber.portNumber(1);
+    private static final HostLocation LOC1 = new HostLocation(DID1, P1, 123L);
+    private static final HostLocation LOC2 = new HostLocation(DID2, P1, 123L);
+
+    private ProxyArpManager proxyArp;
+
+    private TestPacketService packetService;
+
+    private DeviceService deviceService;
+    private LinkService linkService;
+    private HostService hostService;
+
+    @Before
+    public void setUp() throws Exception {
+        proxyArp = new ProxyArpManager();
+        packetService = new TestPacketService();
+        proxyArp.packetService = packetService;
+
+        // Create a host service mock here. Must be replayed by tests once the
+        // expectations have been set up
+        hostService = createMock(HostService.class);
+        proxyArp.hostService = hostService;
+
+        createTopology();
+        proxyArp.deviceService = deviceService;
+        proxyArp.linkService = linkService;
+
+        proxyArp.activate();
+    }
+
+    /**
+     * Creates a fake topology to feed into the ARP module.
+     * <p/>
+     * The default topology is a unidirectional ring topology. Each switch has
+     * 3 ports. Ports 2 and 3 have the links to neighbor switches, and port 1
+     * is free (edge port).
+     */
+    private void createTopology() {
+        deviceService = createMock(DeviceService.class);
+        linkService = createMock(LinkService.class);
+
+        deviceService.addListener(anyObject(DeviceListener.class));
+        linkService.addListener(anyObject(LinkListener.class));
+
+        createDevices(NUM_DEVICES, NUM_PORTS_PER_DEVICE);
+        createLinks(NUM_DEVICES);
+    }
+
+    /**
+     * Creates the devices for the fake topology.
+     */
+    private void createDevices(int numDevices, int numPorts) {
+        List<Device> devices = new ArrayList<>();
+
+        for (int i = 1; i <= numDevices; i++) {
+            DeviceId devId = getDeviceId(i);
+            Device device = createMock(Device.class);
+            expect(device.id()).andReturn(devId).anyTimes();
+            replay(device);
+
+            devices.add(device);
+
+            List<Port> ports = new ArrayList<>();
+            for (int j = 1; j <= numPorts; j++) {
+                Port port = createMock(Port.class);
+                expect(port.number()).andReturn(PortNumber.portNumber(j)).anyTimes();
+                replay(port);
+                ports.add(port);
+            }
+
+            expect(deviceService.getPorts(devId)).andReturn(ports);
+        }
+
+        expect(deviceService.getDevices()).andReturn(devices);
+        replay(deviceService);
+    }
+
+    /**
+     * Creates the links for the fake topology.
+     * NB: Only unidirectional links are created, as for this purpose all we
+     * need is to occupy the ports with some link.
+     */
+    private void createLinks(int numDevices) {
+        List<Link> links = new ArrayList<Link>();
+
+        for (int i = 1; i <= numDevices; i++) {
+            ConnectPoint src = new ConnectPoint(
+                    getDeviceId(i),
+                    PortNumber.portNumber(2));
+            ConnectPoint dst = new ConnectPoint(
+                    getDeviceId((i + 1 > numDevices) ? 1 : i + 1),
+                    PortNumber.portNumber(3));
+
+            Link link = createMock(Link.class);
+            expect(link.src()).andReturn(src).anyTimes();
+            expect(link.dst()).andReturn(dst).anyTimes();
+            replay(link);
+
+            links.add(link);
+        }
+
+        expect(linkService.getLinks()).andReturn(links).anyTimes();
+        replay(linkService);
+    }
+
+    /**
+     * Tests {@link ProxyArpManager#known(IpPrefix)} in the case where the
+     * IP address is not known.
+     * Verifies the method returns false.
+     */
+    @Test
+    public void testNotKnown() {
+        expect(hostService.getHostsByIp(IP1)).andReturn(Collections.<Host>emptySet());
+        replay(hostService);
+
+        assertFalse(proxyArp.known(IP1));
+    }
+
+    /**
+     * Tests {@link ProxyArpManager#known(IpPrefix)} in the case where the
+     * IP address is known.
+     * Verifies the method returns true.
+     */
+    @Test
+    public void testKnown() {
+        Host host1 = createMock(Host.class);
+        Host host2 = createMock(Host.class);
+
+        expect(hostService.getHostsByIp(IP1))
+                .andReturn(Sets.newHashSet(host1, host2));
+        replay(hostService);
+
+        assertTrue(proxyArp.known(IP1));
+    }
+
+    /**
+     * Tests {@link ProxyArpManager#reply(Ethernet)} in the case where the
+     * destination host is known.
+     * Verifies the correct ARP reply is sent out the correct port.
+     */
+    @Test
+    public void testReplyKnown() {
+        Host replyer = new DefaultHost(PID, HID1, MAC1, VLAN1, LOC2,
+                Collections.singleton(IP1));
+
+        Host requestor = new DefaultHost(PID, HID2, MAC2, VLAN1, LOC1,
+                Collections.singleton(IP2));
+
+        expect(hostService.getHostsByIp(IpPrefix.valueOf(IP1.toOctets())))
+                .andReturn(Collections.singleton(replyer));
+        expect(hostService.getHost(HID2)).andReturn(requestor);
+
+        replay(hostService);
+
+        Ethernet arpRequest = buildArp(ARP.OP_REQUEST, MAC2, null, IP2, IP1);
+
+        proxyArp.reply(arpRequest);
+
+        assertEquals(1, packetService.packets.size());
+        Ethernet arpReply = buildArp(ARP.OP_REPLY, MAC1, MAC2, IP1, IP2);
+        verifyPacketOut(arpReply, LOC1, packetService.packets.get(0));
+    }
+
+    /**
+     * Tests {@link ProxyArpManager#reply(Ethernet)} in the case where the
+     * destination host is not known.
+     * Verifies the ARP request is flooded out the correct edge ports.
+     */
+    @Test
+    public void testReplyUnknown() {
+        Host requestor = new DefaultHost(PID, HID2, MAC2, VLAN1, LOC1,
+                Collections.singleton(IP2));
+
+        expect(hostService.getHostsByIp(IpPrefix.valueOf(IP1.toOctets())))
+                .andReturn(Collections.<Host>emptySet());
+        expect(hostService.getHost(HID2)).andReturn(requestor);
+
+        replay(hostService);
+
+        Ethernet arpRequest = buildArp(ARP.OP_REQUEST, MAC2, null, IP2, IP1);
+
+        proxyArp.reply(arpRequest);
+
+        verifyFlood(arpRequest);
+    }
+
+    /**
+     * Tests {@link ProxyArpManager#reply(Ethernet)} in the case where the
+     * destination host is known for that IP address, but is not on the same
+     * VLAN as the source host.
+     * Verifies the ARP request is flooded out the correct edge ports.
+     */
+    @Test
+    public void testReplyDifferentVlan() {
+        Host replyer = new DefaultHost(PID, HID1, MAC1, VLAN2, LOC2,
+                Collections.singleton(IP1));
+
+        Host requestor = new DefaultHost(PID, HID2, MAC2, VLAN1, LOC1,
+                Collections.singleton(IP2));
+
+        expect(hostService.getHostsByIp(IpPrefix.valueOf(IP1.toOctets())))
+                .andReturn(Collections.singleton(replyer));
+        expect(hostService.getHost(HID2)).andReturn(requestor);
+
+        replay(hostService);
+
+        Ethernet arpRequest = buildArp(ARP.OP_REQUEST, MAC2, null, IP2, IP1);
+
+        proxyArp.reply(arpRequest);
+
+        verifyFlood(arpRequest);
+    }
+
+    /**
+     * Tests {@link ProxyArpManager#forward(Ethernet)} in the case where the
+     * destination host is known.
+     * Verifies the correct ARP request is sent out the correct port.
+     */
+    @Test
+    public void testForwardToHost() {
+        Host host1 = new DefaultHost(PID, HID1, MAC1, VLAN1, LOC1,
+                Collections.singleton(IP1));
+
+        expect(hostService.getHost(HID1)).andReturn(host1);
+        replay(hostService);
+
+        Ethernet arpRequest = buildArp(ARP.OP_REPLY, MAC2, MAC1, IP2, IP1);
+
+        proxyArp.forward(arpRequest);
+
+        assertEquals(1, packetService.packets.size());
+        OutboundPacket packet = packetService.packets.get(0);
+
+        verifyPacketOut(arpRequest, LOC1, packet);
+    }
+
+    /**
+     * Tests {@link ProxyArpManager#forward(Ethernet)} in the case where the
+     * destination host is not known.
+     * Verifies the correct ARP request is flooded out the correct edge ports.
+     */
+    @Test
+    public void testForwardFlood() {
+        expect(hostService.getHost(HID1)).andReturn(null);
+        replay(hostService);
+
+        Ethernet arpRequest = buildArp(ARP.OP_REPLY, MAC2, MAC1, IP2, IP1);
+
+        proxyArp.forward(arpRequest);
+
+        verifyFlood(arpRequest);
+    }
+
+    /**
+     * Verifies that the given packet was flooded out all available edge ports.
+     *
+     * @param packet the packet that was expected to be flooded
+     */
+    private void verifyFlood(Ethernet packet) {
+        assertEquals(NUM_FLOOD_PORTS, packetService.packets.size());
+
+        Collections.sort(packetService.packets,
+            new Comparator<OutboundPacket>() {
+                @Override
+                public int compare(OutboundPacket o1, OutboundPacket o2) {
+                    return o1.sendThrough().uri().compareTo(o2.sendThrough().uri());
+                }
+            });
+
+        for (int i = 0; i < NUM_FLOOD_PORTS; i++) {
+            ConnectPoint cp = new ConnectPoint(getDeviceId(i + 1), PortNumber.portNumber(1));
+
+            OutboundPacket outboundPacket = packetService.packets.get(i);
+            verifyPacketOut(packet, cp, outboundPacket);
+        }
+    }
+
+    /**
+     * Verifies the given packet was sent out the given port.
+     *
+     * @param expected the packet that was expected to be sent
+     * @param outPort the port the packet was expected to be sent out
+     * @param actual the actual OutboundPacket to verify
+     */
+    private void verifyPacketOut(Ethernet expected, ConnectPoint outPort,
+            OutboundPacket actual) {
+        assertTrue(Arrays.equals(expected.serialize(), actual.data().array()));
+        assertEquals(1, actual.treatment().instructions().size());
+        assertEquals(outPort.deviceId(), actual.sendThrough());
+        Instruction instruction = actual.treatment().instructions().get(0);
+        assertTrue(instruction instanceof OutputInstruction);
+        assertEquals(outPort.port(), ((OutputInstruction) instruction).port());
+    }
+
+    /**
+     * Returns the device ID of the ith device.
+     *
+     * @param i device to get the ID of
+     * @return the device ID
+     */
+    private static DeviceId getDeviceId(int i) {
+        return DeviceId.deviceId("" + i);
+    }
+
+    /**
+     * Builds an ARP packet with the given parameters.
+     *
+     * @param opcode opcode of the ARP packet
+     * @param srcMac source MAC address
+     * @param dstMac destination MAC address, or null if this is a request
+     * @param srcIp source IP address
+     * @param dstIp destination IP address
+     * @return the ARP packet
+     */
+    private Ethernet buildArp(short opcode, MacAddress srcMac, MacAddress dstMac,
+            IpPrefix srcIp, IpPrefix dstIp) {
+        Ethernet eth = new Ethernet();
+
+        if (dstMac == null) {
+            eth.setDestinationMACAddress(MacAddress.BROADCAST_MAC);
+        } else {
+            eth.setDestinationMACAddress(dstMac.getAddress());
+        }
+
+        eth.setSourceMACAddress(srcMac.getAddress());
+        eth.setEtherType(Ethernet.TYPE_ARP);
+        eth.setVlanID(VLAN1.toShort());
+
+        ARP arp = new ARP();
+        arp.setOpCode(opcode);
+        arp.setProtocolType(ARP.PROTO_TYPE_IP);
+        arp.setHardwareType(ARP.HW_TYPE_ETHERNET);
+
+        arp.setProtocolAddressLength((byte) IpPrefix.INET_LEN);
+        arp.setHardwareAddressLength((byte) Ethernet.DATALAYER_ADDRESS_LENGTH);
+        arp.setSenderHardwareAddress(srcMac.getAddress());
+
+        if (dstMac == null) {
+            arp.setTargetHardwareAddress(MacAddress.ZERO_MAC_ADDRESS);
+        } else {
+            arp.setTargetHardwareAddress(dstMac.getAddress());
+        }
+
+        arp.setSenderProtocolAddress(srcIp.toOctets());
+        arp.setTargetProtocolAddress(dstIp.toOctets());
+
+        eth.setPayload(arp);
+        return eth;
+    }
+
+    /**
+     * Test PacketService implementation that simply stores OutboundPackets
+     * passed to {@link #emit(OutboundPacket)} for later verification.
+     */
+    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);
+        }
+    }
+}