diff --git a/apps/sdnip/src/main/java/org/onlab/onos/sdnip/HostToInterfaceAdaptor.java b/apps/sdnip/src/main/java/org/onlab/onos/sdnip/HostToInterfaceAdaptor.java
index 7a6e6bb..c609b95 100644
--- a/apps/sdnip/src/main/java/org/onlab/onos/sdnip/HostToInterfaceAdaptor.java
+++ b/apps/sdnip/src/main/java/org/onlab/onos/sdnip/HostToInterfaceAdaptor.java
@@ -4,19 +4,17 @@
 
 import java.util.Set;
 
-import org.apache.commons.lang.NotImplementedException;
 import org.onlab.onos.net.ConnectPoint;
 import org.onlab.onos.net.host.HostService;
 import org.onlab.onos.net.host.PortAddresses;
 import org.onlab.onos.sdnip.config.Interface;
 import org.onlab.packet.IpAddress;
+import org.onlab.packet.IpPrefix;
 
 import com.google.common.collect.Sets;
 
-
-
 /**
- * Provides IntefaceService using PortAddresses data from the HostService.
+ * Provides InterfaceService using PortAddresses data from the HostService.
  */
 public class HostToInterfaceAdaptor implements InterfaceService {
 
@@ -52,8 +50,17 @@
 
     @Override
     public Interface getMatchingInterface(IpAddress ipAddress) {
-        // TODO implement
-        throw new NotImplementedException("getMatchingInteface is not yet implemented");
+        checkNotNull(ipAddress);
+
+        for (PortAddresses portAddresses : hostService.getAddressBindings()) {
+            for (IpPrefix p : portAddresses.ips()) {
+                if (p.contains(ipAddress)) {
+                    return new Interface(portAddresses);
+                }
+            }
+        }
+
+        return null;
     }
 
 }
diff --git a/apps/sdnip/src/main/java/org/onlab/onos/sdnip/SdnIp.java b/apps/sdnip/src/main/java/org/onlab/onos/sdnip/SdnIp.java
index 54aa9e5..d66ec9c 100644
--- a/apps/sdnip/src/main/java/org/onlab/onos/sdnip/SdnIp.java
+++ b/apps/sdnip/src/main/java/org/onlab/onos/sdnip/SdnIp.java
@@ -64,6 +64,7 @@
         bgpSessionManager.startUp(2000); // TODO
 
         // TODO need to disable link discovery on external ports
+
     }
 
     @Deactivate
diff --git a/apps/sdnip/src/test/java/org/onlab/onos/sdnip/HostToInterfaceAdaptorTest.java b/apps/sdnip/src/test/java/org/onlab/onos/sdnip/HostToInterfaceAdaptorTest.java
new file mode 100644
index 0000000..5a3dc51
--- /dev/null
+++ b/apps/sdnip/src/test/java/org/onlab/onos/sdnip/HostToInterfaceAdaptorTest.java
@@ -0,0 +1,177 @@
+package org.onlab.onos.sdnip;
+
+import static org.easymock.EasyMock.createMock;
+import static org.easymock.EasyMock.expect;
+import static org.easymock.EasyMock.replay;
+import static org.easymock.EasyMock.reset;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+import java.util.Map;
+import java.util.Set;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.onlab.onos.net.ConnectPoint;
+import org.onlab.onos.net.DeviceId;
+import org.onlab.onos.net.PortNumber;
+import org.onlab.onos.net.host.HostService;
+import org.onlab.onos.net.host.PortAddresses;
+import org.onlab.onos.sdnip.config.Interface;
+import org.onlab.packet.IpAddress;
+import org.onlab.packet.IpPrefix;
+import org.onlab.packet.MacAddress;
+
+import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
+
+/**
+ * Unit tests for the HostToInterfaceAdaptor class.
+ */
+public class HostToInterfaceAdaptorTest {
+
+    private HostService hostService;
+    private HostToInterfaceAdaptor adaptor;
+
+    private Set<PortAddresses> portAddresses;
+    private Map<ConnectPoint, Interface> interfaces;
+
+    private static final ConnectPoint CP1 = new ConnectPoint(
+            DeviceId.deviceId("of:1"), PortNumber.portNumber(1));
+    private static final ConnectPoint CP2 = new ConnectPoint(
+            DeviceId.deviceId("of:1"), PortNumber.portNumber(2));
+    private static final ConnectPoint CP3 = new ConnectPoint(
+            DeviceId.deviceId("of:2"), PortNumber.portNumber(1));
+
+    private static final ConnectPoint NON_EXISTENT_CP = new ConnectPoint(
+            DeviceId.deviceId("doesnotexist"), PortNumber.portNumber(1));
+
+    private static final PortAddresses DEFAULT_PA = new PortAddresses(
+            NON_EXISTENT_CP, null, null);
+
+
+    @Before
+    public void setUp() throws Exception {
+        hostService = createMock(HostService.class);
+
+        portAddresses = Sets.newHashSet();
+        interfaces = Maps.newHashMap();
+
+        createPortAddressesAndInterface(CP1,
+                Sets.newHashSet(IpPrefix.valueOf("192.168.1.1/24")),
+                MacAddress.valueOf("00:00:00:00:00:01"));
+
+        // Two addresses in the same subnet
+        createPortAddressesAndInterface(CP2,
+                Sets.newHashSet(IpPrefix.valueOf("192.168.2.1/24"),
+                        IpPrefix.valueOf("192.168.2.2/24")),
+                MacAddress.valueOf("00:00:00:00:00:02"));
+
+        // Two addresses in different subnets
+        createPortAddressesAndInterface(CP3,
+                Sets.newHashSet(IpPrefix.valueOf("192.168.3.1/24"),
+                        IpPrefix.valueOf("192.168.4.1/24")),
+                MacAddress.valueOf("00:00:00:00:00:03"));
+
+        expect(hostService.getAddressBindings()).andReturn(portAddresses).anyTimes();
+
+        replay(hostService);
+
+        adaptor = new HostToInterfaceAdaptor(hostService);
+    }
+
+    /**
+     * Creates both a PortAddresses and an Interface for the given inputs and
+     * places them in the correct global data stores.
+     *
+     * @param cp the connect point
+     * @param ips the set of IP addresses
+     * @param mac the MAC address
+     */
+    private void createPortAddressesAndInterface(
+            ConnectPoint cp, Set<IpPrefix> ips, MacAddress mac) {
+        PortAddresses pa = new PortAddresses(cp, ips, mac);
+        portAddresses.add(pa);
+        expect(hostService.getAddressBindingsForPort(cp)).andReturn(pa).anyTimes();
+
+        Interface intf = new Interface(cp, ips, mac);
+        interfaces.put(cp, intf);
+    }
+
+    /**
+     * Tests {@link HostToInterfaceAdaptor#getInterfaces()}.
+     * Verifies that the set of interfaces returned matches what is expected
+     * based on the input PortAddresses data.
+     */
+    @Test
+    public void testGetInterfaces() {
+        Set<Interface> adaptorIntfs = adaptor.getInterfaces();
+
+        assertEquals(3, adaptorIntfs.size());
+        assertTrue(adaptorIntfs.contains(this.interfaces.get(CP1)));
+        assertTrue(adaptorIntfs.contains(this.interfaces.get(CP2)));
+        assertTrue(adaptorIntfs.contains(this.interfaces.get(CP3)));
+    }
+
+    /**
+     * Tests {@link HostToInterfaceAdaptor#getInterface(ConnectPoint)}.
+     * Verifies that the correct interface is returned for a given connect
+     * point.
+     */
+    @Test
+    public void testGetInterface() {
+        assertEquals(this.interfaces.get(CP1), adaptor.getInterface(CP1));
+        assertEquals(this.interfaces.get(CP2), adaptor.getInterface(CP2));
+        assertEquals(this.interfaces.get(CP3), adaptor.getInterface(CP3));
+
+        // Try and get an interface for a connect point with no addresses
+        reset(hostService);
+        expect(hostService.getAddressBindingsForPort(NON_EXISTENT_CP))
+                .andReturn(DEFAULT_PA).anyTimes();
+        replay(hostService);
+
+        assertNull(adaptor.getInterface(NON_EXISTENT_CP));
+    }
+
+    /**
+     * Tests {@link HostToInterfaceAdaptor#getInterface(ConnectPoint)} in the
+     * case that the input connect point is null.
+     * Verifies that a NullPointerException is thrown.
+     */
+    @Test(expected = NullPointerException.class)
+    public void testGetInterfaceNull() {
+        adaptor.getInterface(null);
+    }
+
+    /**
+     * Tests {@link HostToInterfaceAdaptor#getMatchingInterface(IpAddress)}.
+     * Verifies that the correct interface is returned based on the given IP
+     * address.
+     */
+    @Test
+    public void testGetMatchingInterface() {
+        assertEquals(this.interfaces.get(CP1),
+                adaptor.getMatchingInterface(IpAddress.valueOf("192.168.1.100")));
+        assertEquals(this.interfaces.get(CP2),
+                adaptor.getMatchingInterface(IpAddress.valueOf("192.168.2.100")));
+        assertEquals(this.interfaces.get(CP3),
+                adaptor.getMatchingInterface(IpAddress.valueOf("192.168.3.100")));
+        assertEquals(this.interfaces.get(CP3),
+                adaptor.getMatchingInterface(IpAddress.valueOf("192.168.4.100")));
+
+        // Try and match an address we don't have subnet configured for
+        assertNull(adaptor.getMatchingInterface(IpAddress.valueOf("1.1.1.1")));
+    }
+
+    /**
+     * Tests {@link HostToInterfaceAdaptor#getMatchingInterface(IpAddress)} in the
+     * case that the input IP address is null.
+     * Verifies that a NullPointerException is thrown.
+     */
+    @Test(expected = NullPointerException.class)
+    public void testGetMatchingInterfaceNull() {
+        adaptor.getMatchingInterface(null);
+    }
+
+}