diff --git a/service/src/com/android/server/connectivity/AutomaticOnOffKeepaliveTracker.java b/service/src/com/android/server/connectivity/AutomaticOnOffKeepaliveTracker.java
index f8285ed..62d79a3 100644
--- a/service/src/com/android/server/connectivity/AutomaticOnOffKeepaliveTracker.java
+++ b/service/src/com/android/server/connectivity/AutomaticOnOffKeepaliveTracker.java
@@ -18,6 +18,7 @@
 
 import static android.net.SocketKeepalive.ERROR_INVALID_SOCKET;
 import static android.net.SocketKeepalive.MIN_INTERVAL_SEC;
+import static android.net.SocketKeepalive.SUCCESS;
 import static android.net.SocketKeepalive.SUCCESS_PAUSED;
 import static android.provider.DeviceConfig.NAMESPACE_TETHERING;
 import static android.system.OsConstants.AF_INET;
@@ -52,6 +53,7 @@
 import android.system.StructTimeval;
 import android.util.LocalLog;
 import android.util.Log;
+import android.util.Pair;
 import android.util.SparseArray;
 
 import com.android.internal.annotations.VisibleForTesting;
@@ -381,7 +383,11 @@
             return;
         }
         autoKi.mAutomaticOnOffState = STATE_ENABLED;
-        handleResumeKeepalive(newKi);
+        final int error = handleResumeKeepalive(newKi);
+        if (error != SUCCESS) {
+            // Failed to start the keepalive
+            cleanupAutoOnOffKeepalive(autoKi);
+        }
     }
 
     /**
@@ -402,7 +408,20 @@
      * Forward to KeepaliveTracker.
      */
     public void handleEventSocketKeepalive(@NonNull NetworkAgentInfo nai, int slot, int reason) {
-        mKeepaliveTracker.handleEventSocketKeepalive(nai, slot, reason);
+        if (mKeepaliveTracker.handleEventSocketKeepalive(nai, slot, reason)) return;
+
+        // The keepalive was stopped and so the autoKi should be cleaned up.
+        final AutomaticOnOffKeepalive autoKi =
+                CollectionUtils.findFirst(
+                        mAutomaticOnOffKeepalives, it -> it.match(nai.network(), slot));
+        if (autoKi == null) {
+            // This may occur when the autoKi gets cleaned up elsewhere (i.e
+            // handleCheckKeepalivesStillValid) while waiting for the network agent to
+            // start the keepalive and the network agent returns an error event.
+            Log.e(TAG, "Attempt cleanup on unknown network, slot");
+            return;
+        }
+        cleanupAutoOnOffKeepalive(autoKi);
     }
 
     /**
@@ -414,6 +433,9 @@
         final List<AutomaticOnOffKeepalive> matches =
                 CollectionUtils.filter(mAutomaticOnOffKeepalives, it -> it.mKi.getNai() == nai);
         for (final AutomaticOnOffKeepalive ki : matches) {
+            if (ki.mAutomaticOnOffState == STATE_SUSPENDED) {
+                mKeepaliveTracker.finalizePausedKeepalive(ki.mKi, reason);
+            }
             cleanupAutoOnOffKeepalive(ki);
         }
     }
@@ -425,9 +447,14 @@
      */
     public void handleStartKeepalive(Message message) {
         final AutomaticOnOffKeepalive autoKi = (AutomaticOnOffKeepalive) message.obj;
+        final int error = mKeepaliveTracker.handleStartKeepalive(autoKi.mKi);
+        if (error != SUCCESS) {
+            mEventLog.log("Failed to start keepalive " + autoKi.mCallback + " on "
+                    + autoKi.getNetwork() + " with error " + error);
+            return;
+        }
         mEventLog.log("Start keepalive " + autoKi.mCallback + " on " + autoKi.getNetwork());
         mKeepaliveStatsTracker.onStartKeepalive();
-        mKeepaliveTracker.handleStartKeepalive(autoKi.mKi);
 
         // Add automatic on/off request into list to track its life cycle.
         try {
@@ -443,10 +470,22 @@
         }
     }
 
-    private void handleResumeKeepalive(@NonNull final KeepaliveTracker.KeepaliveInfo ki) {
+    /**
+     * Handle resume keepalive with the given KeepaliveInfo
+     *
+     * @return SUCCESS if the keepalive is successfully starting and the error reason otherwise.
+     */
+    private int handleResumeKeepalive(@NonNull final KeepaliveTracker.KeepaliveInfo ki) {
+        final int error = mKeepaliveTracker.handleStartKeepalive(ki);
+        if (error != SUCCESS) {
+            mEventLog.log("Failed to resume keepalive " + ki.mCallback + " on " + ki.mNai
+                    + " with error " + error);
+            return error;
+        }
         mKeepaliveStatsTracker.onResumeKeepalive();
-        mKeepaliveTracker.handleStartKeepalive(ki);
         mEventLog.log("Resumed successfully keepalive " + ki.mCallback + " on " + ki.mNai);
+
+        return SUCCESS;
     }
 
     private void handlePauseKeepalive(@NonNull final KeepaliveTracker.KeepaliveInfo ki) {
@@ -467,7 +506,7 @@
             final KeepaliveTracker.KeepaliveInfo ki = autoKi.mKi;
             mKeepaliveTracker.handleStopKeepalive(ki.getNai(), ki.getSlot(), reason);
         } else {
-            mKeepaliveTracker.finalizePausedKeepalive(autoKi.mKi);
+            mKeepaliveTracker.finalizePausedKeepalive(autoKi.mKi, reason);
         }
 
         cleanupAutoOnOffKeepalive(autoKi);
@@ -612,7 +651,22 @@
      * Forward to KeepaliveTracker.
      */
     public void handleCheckKeepalivesStillValid(NetworkAgentInfo nai) {
-        mKeepaliveTracker.handleCheckKeepalivesStillValid(nai);
+        ArrayList<Pair<AutomaticOnOffKeepalive, Integer>> invalidKeepalives = null;
+
+        for (final AutomaticOnOffKeepalive autoKi : mAutomaticOnOffKeepalives) {
+            if (!nai.equals(autoKi.mKi.mNai)) continue;
+            final int error = autoKi.mKi.isValid();
+            if (error != SUCCESS) {
+                if (invalidKeepalives == null) {
+                    invalidKeepalives = new ArrayList<>();
+                }
+                invalidKeepalives.add(Pair.create(autoKi, error));
+            }
+        }
+        if (invalidKeepalives == null) return;
+        for (final Pair<AutomaticOnOffKeepalive, Integer> keepaliveAndError : invalidKeepalives) {
+            handleStopKeepalive(keepaliveAndError.first, keepaliveAndError.second);
+        }
     }
 
     @VisibleForTesting
diff --git a/service/src/com/android/server/connectivity/KeepaliveTracker.java b/service/src/com/android/server/connectivity/KeepaliveTracker.java
index cc226ce..941b616 100644
--- a/service/src/com/android/server/connectivity/KeepaliveTracker.java
+++ b/service/src/com/android/server/connectivity/KeepaliveTracker.java
@@ -54,7 +54,6 @@
 import android.system.ErrnoException;
 import android.system.Os;
 import android.util.Log;
-import android.util.Pair;
 
 import com.android.connectivity.resources.R;
 import com.android.internal.annotations.VisibleForTesting;
@@ -337,7 +336,12 @@
             return SUCCESS;
         }
 
-        private int isValid() {
+        /**
+         * Checks if the keepalive info is valid to start.
+         *
+         * @return SUCCESS if the keepalive is valid and the error reason otherwise.
+         */
+        public int isValid() {
             synchronized (mNai) {
                 int error = checkInterval();
                 if (error == SUCCESS) error = checkLimit();
@@ -348,11 +352,17 @@
             }
         }
 
-        void start(int slot) {
+        /**
+         * Attempt to start the keepalive on the given slot.
+         *
+         * @param slot the slot to start the keepalive on.
+         * @return SUCCESS if the keepalive is successfully starting and the error reason otherwise.
+         */
+        int start(int slot) {
             // BINDER_DIED can happen if the binder died before the KeepaliveInfo was created and
             // the constructor set the state to BINDER_DIED. If that's the case, the KI is already
             // cleaned up.
-            if (BINDER_DIED == mStartedState) return;
+            if (BINDER_DIED == mStartedState) return BINDER_DIED;
             mSlot = slot;
             int error = isValid();
             if (error == SUCCESS) {
@@ -368,7 +378,7 @@
                             mTcpController.startSocketMonitor(mFd, this, mSlot);
                         } catch (InvalidSocketException e) {
                             handleStopKeepalive(mNai, mSlot, ERROR_INVALID_SOCKET);
-                            return;
+                            return ERROR_INVALID_SOCKET;
                         }
                         final TcpKeepalivePacketData tcpData = (TcpKeepalivePacketData) mPacket;
                         mNai.onAddTcpKeepalivePacketFilter(slot, tcpData);
@@ -377,13 +387,14 @@
                         break;
                     default:
                         Log.wtf(TAG, "Starting keepalive with unknown type: " + mType);
-                        handleStopKeepalive(mNai, mSlot, error);
-                        return;
+                        handleStopKeepalive(mNai, mSlot, ERROR_UNSUPPORTED);
+                        return ERROR_UNSUPPORTED;
                 }
                 mStartedState = STARTING;
+                return SUCCESS;
             } else {
                 handleStopKeepalive(mNai, mSlot, error);
-                return;
+                return error;
             }
         }
 
@@ -444,6 +455,8 @@
             }
         }
 
+        // TODO: This does not clean up the autoKi in AutomaticOnOffKeepaliveTracker and it is not
+        // possible without a big refactor.
         void onFileDescriptorInitiatedStop(final int socketKeepaliveReason) {
             handleStopKeepalive(mNai, mSlot, socketKeepaliveReason);
         }
@@ -486,12 +499,15 @@
 
     /**
      * Handle start keepalives with the message.
+     *
+     * @param ki the keepalive to start.
+     * @return SUCCESS if the keepalive is successfully starting and the error reason otherwise.
      */
-    public void handleStartKeepalive(KeepaliveInfo ki) {
+    public int handleStartKeepalive(KeepaliveInfo ki) {
         NetworkAgentInfo nai = ki.getNai();
         int slot = findFirstFreeSlot(nai);
         mKeepalives.get(nai).put(slot, ki);
-        ki.start(slot);
+        return ki.start(slot);
     }
 
     public void handleStopAllKeepalives(NetworkAgentInfo nai, int reason) {
@@ -593,40 +609,33 @@
     /**
      * Finalize a paused keepalive.
      *
-     * This will simply send the onStopped() callback after checking that this keepalive is
-     * indeed paused.
+     * This will send the appropriate callback after checking that this keepalive is indeed paused.
      *
      * @param ki the keepalive to finalize
+     * @param reason the reason the keepalive is stopped
      */
-    public void finalizePausedKeepalive(@NonNull final KeepaliveInfo ki) {
+    public void finalizePausedKeepalive(@NonNull final KeepaliveInfo ki, int reason) {
         if (SUCCESS_PAUSED != ki.mStopReason) {
             throw new IllegalStateException("Keepalive is not paused");
         }
-        try {
-            ki.mCallback.onStopped();
-        } catch (RemoteException e) {
-            Log.w(TAG, "Discarded onStopped callback while finalizing paused keepalive");
+        if (reason == SUCCESS) {
+            try {
+                ki.mCallback.onStopped();
+            } catch (RemoteException e) {
+                Log.w(TAG, "Discarded onStopped callback while finalizing paused keepalive");
+            }
+        } else {
+            notifyErrorCallback(ki.mCallback, reason);
         }
     }
 
-    public void handleCheckKeepalivesStillValid(NetworkAgentInfo nai) {
-        HashMap <Integer, KeepaliveInfo> networkKeepalives = mKeepalives.get(nai);
-        if (networkKeepalives != null) {
-            ArrayList<Pair<Integer, Integer>> invalidKeepalives = new ArrayList<>();
-            for (int slot : networkKeepalives.keySet()) {
-                int error = networkKeepalives.get(slot).isValid();
-                if (error != SUCCESS) {
-                    invalidKeepalives.add(Pair.create(slot, error));
-                }
-            }
-            for (Pair<Integer, Integer> slotAndError: invalidKeepalives) {
-                handleStopKeepalive(nai, slotAndError.first, slotAndError.second);
-            }
-        }
-    }
-
-    /** Handle keepalive events from lower layer. */
-    public void handleEventSocketKeepalive(@NonNull NetworkAgentInfo nai, int slot, int reason) {
+    /**
+     * Handle keepalive events from lower layer.
+     *
+     * @return false if the event caused handleStopKeepalive to be called, i.e. the keepalive is
+     *     forced to stop. Otherwise, return true.
+     */
+    public boolean handleEventSocketKeepalive(@NonNull NetworkAgentInfo nai, int slot, int reason) {
         KeepaliveInfo ki = null;
         try {
             ki = mKeepalives.get(nai).get(slot);
@@ -634,7 +643,7 @@
         if (ki == null) {
             Log.e(TAG, "Event " + NetworkAgent.EVENT_SOCKET_KEEPALIVE + "," + slot + "," + reason
                     + " for unknown keepalive " + slot + " on " + nai.toShortString());
-            return;
+            return true;
         }
 
         // This can be called in a number of situations :
@@ -667,11 +676,13 @@
                     Log.w(TAG, "Discarded " + (ki.mResumed ? "onResumed" : "onStarted")
                             + " callback for slot " + slot);
                 }
+                return true;
             } else {
                 Log.d(TAG, "Failed to start keepalive " + slot + " on " + nai.toShortString()
                         + ": " + reason);
                 // The message indicated some error trying to start: do call handleStopKeepalive.
                 handleStopKeepalive(nai, slot, reason);
+                return false;
             }
         } else if (KeepaliveInfo.STOPPING == ki.mStartedState) {
             // The message indicated result of stopping : clean up keepalive slots.
@@ -679,9 +690,12 @@
                     + " stopped: " + reason);
             ki.mStartedState = KeepaliveInfo.NOT_STARTED;
             cleanupStoppedKeepalive(nai, slot);
+            return true;
         } else {
             Log.wtf(TAG, "Event " + NetworkAgent.EVENT_SOCKET_KEEPALIVE + "," + slot + "," + reason
                     + " for keepalive in wrong state: " + ki.toString());
+            // Although this is an unexpected event, the keepalive is not stopped here.
+            return true;
         }
     }
 
diff --git a/tests/unit/java/com/android/server/connectivity/AutomaticOnOffKeepaliveTrackerTest.java b/tests/unit/java/com/android/server/connectivity/AutomaticOnOffKeepaliveTrackerTest.java
index 9e0435d..608e6d8 100644
--- a/tests/unit/java/com/android/server/connectivity/AutomaticOnOffKeepaliveTrackerTest.java
+++ b/tests/unit/java/com/android/server/connectivity/AutomaticOnOffKeepaliveTrackerTest.java
@@ -20,9 +20,12 @@
 import static android.net.ConnectivityManager.TYPE_MOBILE;
 import static android.net.NetworkCapabilities.TRANSPORT_CELLULAR;
 
+import static com.android.testutils.HandlerUtils.visibleOnHandlerThread;
+
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
 import static org.mockito.ArgumentMatchers.any;
@@ -30,17 +33,20 @@
 import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.ArgumentMatchers.longThat;
+import static org.mockito.Mockito.clearInvocations;
 import static org.mockito.Mockito.doNothing;
 import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.ignoreStubs;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
 
 import android.app.AlarmManager;
 import android.content.Context;
 import android.content.res.Resources;
 import android.net.INetd;
 import android.net.ISocketKeepaliveCallback;
-import android.net.KeepalivePacketData;
 import android.net.LinkAddress;
 import android.net.LinkProperties;
 import android.net.MarkMaskParcel;
@@ -48,6 +54,7 @@
 import android.net.Network;
 import android.net.NetworkCapabilities;
 import android.net.NetworkInfo;
+import android.net.SocketKeepalive;
 import android.os.Binder;
 import android.os.Build;
 import android.os.Handler;
@@ -63,6 +70,7 @@
 import androidx.annotation.Nullable;
 
 import com.android.connectivity.resources.R;
+import com.android.server.connectivity.AutomaticOnOffKeepaliveTracker.AutomaticOnOffKeepalive;
 import com.android.server.connectivity.KeepaliveTracker.KeepaliveInfo;
 import com.android.testutils.DevSdkIgnoreRule;
 import com.android.testutils.DevSdkIgnoreRunner;
@@ -70,6 +78,7 @@
 
 import libcore.util.HexEncoding;
 
+import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -82,12 +91,15 @@
 import java.net.Socket;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
+import java.util.ArrayList;
+import java.util.List;
 
 @RunWith(DevSdkIgnoreRunner.class)
 @SmallTest
 @DevSdkIgnoreRule.IgnoreUpTo(Build.VERSION_CODES.TIRAMISU)
 public class AutomaticOnOffKeepaliveTrackerTest {
     private static final String TAG = AutomaticOnOffKeepaliveTrackerTest.class.getSimpleName();
+    private static final int TEST_SLOT = 1;
     private static final int TEST_NETID = 0xA85;
     private static final int TEST_NETID_FWMARK = 0x0A85;
     private static final int OTHER_NETID = 0x1A85;
@@ -95,6 +107,8 @@
     private static final int TIMEOUT_MS = 30_000;
     private static final int MOCK_RESOURCE_ID = 5;
     private static final int TEST_KEEPALIVE_INTERVAL_SEC = 10;
+    private static final int TEST_KEEPALIVE_INVALID_INTERVAL_SEC = 9;
+
     private AutomaticOnOffKeepaliveTracker mAOOKeepaliveTracker;
     private HandlerThread mHandlerThread;
 
@@ -102,6 +116,8 @@
     @Mock AutomaticOnOffKeepaliveTracker.Dependencies mDependencies;
     @Mock Context mCtx;
     @Mock AlarmManager mAlarmManager;
+    @Mock NetworkAgentInfo mNai;
+
     TestKeepaliveTracker mKeepaliveTracker;
     AOOTestHandler mTestHandler;
 
@@ -202,6 +218,37 @@
     private static final byte[] TEST_RESPONSE_BYTES =
             HexEncoding.decode(TEST_RESPONSE_HEX.toCharArray(), false);
 
+    private static class TestKeepaliveInfo {
+        private static List<Socket> sOpenSockets = new ArrayList<>();
+
+        public static void closeAllSockets() throws Exception {
+            for (final Socket socket : sOpenSockets) {
+                socket.close();
+            }
+            sOpenSockets.clear();
+        }
+
+        public final Socket socket;
+        public final Binder binder;
+        public final FileDescriptor fd;
+        public final ISocketKeepaliveCallback socketKeepaliveCallback;
+        public final Network underpinnedNetwork;
+        public final NattKeepalivePacketData kpd;
+
+        TestKeepaliveInfo(NattKeepalivePacketData kpd) throws Exception {
+            this.kpd = kpd;
+            socket = new Socket();
+            socket.bind(null);
+            sOpenSockets.add(socket);
+            fd = socket.getFileDescriptor$();
+
+            binder = new Binder();
+            socketKeepaliveCallback = mock(ISocketKeepaliveCallback.class);
+            doReturn(binder).when(socketKeepaliveCallback).asBinder();
+            underpinnedNetwork = mock(Network.class);
+        }
+    }
+
     private class TestKeepaliveTracker extends KeepaliveTracker {
         private KeepaliveInfo mKi;
 
@@ -231,6 +278,14 @@
     public void setup() throws Exception {
         MockitoAnnotations.initMocks(this);
 
+        mNai.networkCapabilities =
+                new NetworkCapabilities.Builder().addTransportType(TRANSPORT_CELLULAR).build();
+        mNai.networkInfo = new NetworkInfo(TYPE_MOBILE, 0 /* subtype */, "LTE", "LTE");
+        mNai.networkInfo.setDetailedState(
+                NetworkInfo.DetailedState.CONNECTED, "test reason", "test extra info");
+        doReturn(new Network(TEST_NETID)).when(mNai).network();
+        mNai.linkProperties = new LinkProperties();
+
         doReturn(PERMISSION_GRANTED).when(mCtx).checkPermission(any() /* permission */,
                 anyInt() /* pid */, anyInt() /* uid */);
         ConnectivityResources.setResourcesContextForTest(mCtx);
@@ -255,6 +310,11 @@
                 new AutomaticOnOffKeepaliveTracker(mCtx, mTestHandler, mDependencies);
     }
 
+    @After
+    public void teardown() throws Exception {
+        TestKeepaliveInfo.closeAllSockets();
+    }
+
     private final class AOOTestHandler extends Handler {
         public AutomaticOnOffKeepaliveTracker.AutomaticOnOffKeepalive mLastAutoKi = null;
 
@@ -305,45 +365,70 @@
                 () -> assertFalse(mAOOKeepaliveTracker.isAnyTcpSocketConnected(TEST_NETID)));
     }
 
-    @Test
-    public void testAlarm() throws Exception {
+    private void triggerEventKeepalive(int slot, int reason) {
+        visibleOnHandlerThread(
+                mTestHandler,
+                () -> mAOOKeepaliveTracker.handleEventSocketKeepalive(mNai, slot, reason));
+    }
+
+    private TestKeepaliveInfo doStartNattKeepalive(int intervalSeconds) throws Exception {
         final InetAddress srcAddress = InetAddress.getByAddress(
                 new byte[] { (byte) 192, 0, 0, (byte) 129 });
         final int srcPort = 12345;
-        final InetAddress dstAddress = InetAddress.getByAddress(new byte[] { 8, 8, 8, 8});
+        final InetAddress dstAddress = InetAddress.getByAddress(new byte[] {8, 8, 8, 8});
         final int dstPort = 12345;
 
-        final NetworkAgentInfo nai = mock(NetworkAgentInfo.class);
-        nai.networkCapabilities = new NetworkCapabilities.Builder()
-                .addTransportType(TRANSPORT_CELLULAR).build();
-        nai.networkInfo = new NetworkInfo(TYPE_MOBILE, 0 /* subtype */, "LTE", "LTE");
-        nai.networkInfo.setDetailedState(NetworkInfo.DetailedState.CONNECTED, "test reason",
-                "test extra info");
-        nai.linkProperties = new LinkProperties();
-        nai.linkProperties.addLinkAddress(new LinkAddress(srcAddress, 24));
+        mNai.linkProperties.addLinkAddress(new LinkAddress(srcAddress, 24));
 
-        final Socket socket = new Socket();
-        socket.bind(null);
-        final FileDescriptor fd = socket.getFileDescriptor$();
-        final IBinder binder = new Binder();
-        final ISocketKeepaliveCallback cb = mock(ISocketKeepaliveCallback.class);
-        doReturn(binder).when(cb).asBinder();
-        final Network underpinnedNetwork = mock(Network.class);
-
-        final KeepalivePacketData kpd = new NattKeepalivePacketData(srcAddress, srcPort,
+        final NattKeepalivePacketData kpd = new NattKeepalivePacketData(srcAddress, srcPort,
                 dstAddress, dstPort, new byte[] {1});
-        final KeepaliveInfo ki = mKeepaliveTracker.new KeepaliveInfo(cb, nai, kpd,
-                TEST_KEEPALIVE_INTERVAL_SEC, KeepaliveInfo.TYPE_NATT, fd);
+
+        final TestKeepaliveInfo testInfo = new TestKeepaliveInfo(kpd);
+
+        final KeepaliveInfo ki = mKeepaliveTracker.new KeepaliveInfo(
+                testInfo.socketKeepaliveCallback, mNai, kpd, intervalSeconds,
+                KeepaliveInfo.TYPE_NATT, testInfo.fd);
         mKeepaliveTracker.setReturnedKeepaliveInfo(ki);
 
+        mAOOKeepaliveTracker.startNattKeepalive(mNai, testInfo.fd, intervalSeconds,
+                testInfo.socketKeepaliveCallback, srcAddress.toString(), srcPort,
+                dstAddress.toString(), dstPort, true /* automaticOnOffKeepalives */,
+                testInfo.underpinnedNetwork);
+        HandlerUtils.waitForIdle(mTestHandler, TIMEOUT_MS);
+
+        return testInfo;
+    }
+
+    private TestKeepaliveInfo doStartNattKeepalive() throws Exception {
+        return doStartNattKeepalive(TEST_KEEPALIVE_INTERVAL_SEC);
+    }
+
+    private void doPauseKeepalive(AutomaticOnOffKeepalive autoKi) throws Exception {
+        setupResponseWithoutSocketExisting();
+        visibleOnHandlerThread(
+                mTestHandler,
+                () -> mAOOKeepaliveTracker.handleMonitorAutomaticKeepalive(autoKi, TEST_NETID));
+    }
+
+    private void doResumeKeepalive(AutomaticOnOffKeepalive autoKi) throws Exception {
+        setupResponseWithSocketExisting();
+        visibleOnHandlerThread(
+                mTestHandler,
+                () -> mAOOKeepaliveTracker.handleMonitorAutomaticKeepalive(autoKi, TEST_NETID));
+    }
+
+    private void doStopKeepalive(AutomaticOnOffKeepalive autoKi) throws Exception {
+        visibleOnHandlerThread(
+                mTestHandler,
+                () -> mAOOKeepaliveTracker.handleStopKeepalive(autoKi, SocketKeepalive.SUCCESS));
+    }
+
+    @Test
+    public void testAlarm() throws Exception {
         // Mock elapsed real time to verify the alarm timer.
         final long time = SystemClock.elapsedRealtime();
         doReturn(time).when(mDependencies).getElapsedRealtime();
-
-        mAOOKeepaliveTracker.startNattKeepalive(nai, fd, 10 /* intervalSeconds */, cb,
-                srcAddress.toString(), srcPort, dstAddress.toString(), dstPort,
-                true /* automaticOnOffKeepalives */, underpinnedNetwork);
-        HandlerUtils.waitForIdle(mTestHandler, TIMEOUT_MS);
+        final TestKeepaliveInfo testInfo = doStartNattKeepalive();
 
         final ArgumentCaptor<AlarmManager.OnAlarmListener> listenerCaptor =
                 ArgumentCaptor.forClass(AlarmManager.OnAlarmListener.class);
@@ -362,9 +447,8 @@
         HandlerUtils.waitForIdle(mTestHandler, TIMEOUT_MS);
 
         assertNotNull(mTestHandler.mLastAutoKi);
-        assertEquals(cb, mTestHandler.mLastAutoKi.getCallback());
-        assertEquals(underpinnedNetwork, mTestHandler.mLastAutoKi.getUnderpinnedNetwork());
-        socket.close();
+        assertEquals(testInfo.socketKeepaliveCallback, mTestHandler.mLastAutoKi.getCallback());
+        assertEquals(testInfo.underpinnedNetwork, mTestHandler.mLastAutoKi.getUnderpinnedNetwork());
     }
 
     private void setupResponseWithSocketExisting() throws Exception {
@@ -391,4 +475,301 @@
         buffer.order(ByteOrder.nativeOrder());
         return buffer;
     }
+
+    private AutomaticOnOffKeepalive getAutoKiForBinder(IBinder binder) {
+        return visibleOnHandlerThread(
+                mTestHandler, () -> mAOOKeepaliveTracker.getKeepaliveForBinder(binder));
+    }
+
+    private void checkAndProcessKeepaliveStart(final NattKeepalivePacketData kpd) throws Exception {
+        checkAndProcessKeepaliveStart(TEST_SLOT, kpd);
+    }
+
+    private void checkAndProcessKeepaliveStart(
+            int slot, final NattKeepalivePacketData kpd) throws Exception {
+        verify(mNai).onStartNattSocketKeepalive(slot, TEST_KEEPALIVE_INTERVAL_SEC, kpd);
+        verify(mNai).onAddNattKeepalivePacketFilter(slot, kpd);
+        triggerEventKeepalive(slot, SocketKeepalive.SUCCESS);
+    }
+
+    private void checkAndProcessKeepaliveStop() throws Exception {
+        checkAndProcessKeepaliveStop(TEST_SLOT);
+    }
+
+    private void checkAndProcessKeepaliveStop(int slot) throws Exception {
+        verify(mNai).onStopSocketKeepalive(slot);
+        verify(mNai).onRemoveKeepalivePacketFilter(slot);
+        triggerEventKeepalive(slot, SocketKeepalive.SUCCESS);
+    }
+
+    @Test
+    public void testStartNattKeepalive_valid() throws Exception {
+        final TestKeepaliveInfo testInfo = doStartNattKeepalive();
+
+        checkAndProcessKeepaliveStart(testInfo.kpd);
+
+        final AutomaticOnOffKeepalive autoKi = getAutoKiForBinder(testInfo.binder);
+        assertNotNull(autoKi);
+        assertEquals(testInfo.socketKeepaliveCallback, autoKi.getCallback());
+
+        verify(testInfo.socketKeepaliveCallback).onStarted();
+        verifyNoMoreInteractions(ignoreStubs(testInfo.socketKeepaliveCallback));
+    }
+
+    @Test
+    public void testStartNattKeepalive_invalidInterval() throws Exception {
+        final TestKeepaliveInfo testInfo =
+                doStartNattKeepalive(TEST_KEEPALIVE_INVALID_INTERVAL_SEC);
+
+        assertNull(getAutoKiForBinder(testInfo.binder));
+
+        verify(testInfo.socketKeepaliveCallback).onError(SocketKeepalive.ERROR_INVALID_INTERVAL);
+        verifyNoMoreInteractions(ignoreStubs(testInfo.socketKeepaliveCallback));
+    }
+
+    @Test
+    public void testHandleEventSocketKeepalive_startingFailureHardwareError() throws Exception {
+        final TestKeepaliveInfo testInfo = doStartNattKeepalive();
+
+        verify(mNai)
+                .onStartNattSocketKeepalive(TEST_SLOT, TEST_KEEPALIVE_INTERVAL_SEC, testInfo.kpd);
+        verify(mNai).onAddNattKeepalivePacketFilter(TEST_SLOT, testInfo.kpd);
+        // Network agent returns an error, fails to start the keepalive.
+        triggerEventKeepalive(TEST_SLOT, SocketKeepalive.ERROR_HARDWARE_ERROR);
+
+        checkAndProcessKeepaliveStop();
+
+        assertNull(getAutoKiForBinder(testInfo.binder));
+
+        verify(testInfo.socketKeepaliveCallback).onError(SocketKeepalive.ERROR_HARDWARE_ERROR);
+        verifyNoMoreInteractions(ignoreStubs(testInfo.socketKeepaliveCallback));
+    }
+
+    @Test
+    public void testHandleCheckKeepalivesStillValid_linkPropertiesChanged() throws Exception {
+        // Successful start of NATT keepalive.
+        final TestKeepaliveInfo testInfo = doStartNattKeepalive();
+        checkAndProcessKeepaliveStart(testInfo.kpd);
+        verify(testInfo.socketKeepaliveCallback).onStarted();
+
+        // Source address is removed from link properties by clearing.
+        mNai.linkProperties.clear();
+
+        // Check for valid keepalives
+        visibleOnHandlerThread(
+                mTestHandler, () -> mAOOKeepaliveTracker.handleCheckKeepalivesStillValid(mNai));
+
+        checkAndProcessKeepaliveStop();
+
+        assertNull(getAutoKiForBinder(testInfo.binder));
+
+        verify(testInfo.socketKeepaliveCallback).onError(SocketKeepalive.ERROR_INVALID_IP_ADDRESS);
+        verifyNoMoreInteractions(ignoreStubs(testInfo.socketKeepaliveCallback));
+    }
+
+    @Test
+    public void testStopKeepalive() throws Exception {
+        // Successful start of NATT keepalive.
+        final TestKeepaliveInfo testInfo = doStartNattKeepalive();
+        checkAndProcessKeepaliveStart(testInfo.kpd);
+        verify(testInfo.socketKeepaliveCallback).onStarted();
+
+        doStopKeepalive(getAutoKiForBinder(testInfo.binder));
+        checkAndProcessKeepaliveStop();
+
+        assertNull(getAutoKiForBinder(testInfo.binder));
+        verify(testInfo.socketKeepaliveCallback).onStopped();
+        verifyNoMoreInteractions(ignoreStubs(testInfo.socketKeepaliveCallback));
+    }
+
+    @Test
+    public void testPauseKeepalive() throws Exception {
+        // Successful start of NATT keepalive.
+        final TestKeepaliveInfo testInfo = doStartNattKeepalive();
+        checkAndProcessKeepaliveStart(testInfo.kpd);
+        verify(testInfo.socketKeepaliveCallback).onStarted();
+
+        doPauseKeepalive(getAutoKiForBinder(testInfo.binder));
+
+        checkAndProcessKeepaliveStop();
+        verify(testInfo.socketKeepaliveCallback).onPaused();
+
+        // Pausing does not cleanup the autoKi
+        assertNotNull(getAutoKiForBinder(testInfo.binder));
+
+        clearInvocations(mNai);
+        doStopKeepalive(getAutoKiForBinder(testInfo.binder));
+        // The keepalive is already stopped.
+        verify(mNai, never()).onStopSocketKeepalive(TEST_SLOT);
+        verify(mNai, never()).onRemoveKeepalivePacketFilter(TEST_SLOT);
+
+        // Stopping while paused still calls onStopped.
+        verify(testInfo.socketKeepaliveCallback).onStopped();
+        // autoKi is cleaned up.
+        assertNull(getAutoKiForBinder(testInfo.binder));
+
+        verifyNoMoreInteractions(ignoreStubs(testInfo.socketKeepaliveCallback));
+    }
+
+    @Test
+    public void testResumeKeepalive() throws Exception {
+        // Successful start of NATT keepalive.
+        final TestKeepaliveInfo testInfo = doStartNattKeepalive();
+        checkAndProcessKeepaliveStart(testInfo.kpd);
+        verify(testInfo.socketKeepaliveCallback).onStarted();
+
+        doPauseKeepalive(getAutoKiForBinder(testInfo.binder));
+        checkAndProcessKeepaliveStop();
+        verify(testInfo.socketKeepaliveCallback).onPaused();
+
+        clearInvocations(mNai);
+        doResumeKeepalive(getAutoKiForBinder(testInfo.binder));
+        checkAndProcessKeepaliveStart(testInfo.kpd);
+        assertNotNull(getAutoKiForBinder(testInfo.binder));
+        verify(testInfo.socketKeepaliveCallback).onResumed();
+
+        doStopKeepalive(getAutoKiForBinder(testInfo.binder));
+        checkAndProcessKeepaliveStop();
+        assertNull(getAutoKiForBinder(testInfo.binder));
+
+        verify(testInfo.socketKeepaliveCallback).onStopped();
+        verifyNoMoreInteractions(ignoreStubs(testInfo.socketKeepaliveCallback));
+    }
+
+    @Test
+    public void testResumeKeepalive_invalidSourceAddress() throws Exception {
+        // Successful start of NATT keepalive.
+        final TestKeepaliveInfo testInfo = doStartNattKeepalive();
+        checkAndProcessKeepaliveStart(testInfo.kpd);
+        verify(testInfo.socketKeepaliveCallback).onStarted();
+
+        doPauseKeepalive(getAutoKiForBinder(testInfo.binder));
+        checkAndProcessKeepaliveStop();
+        verify(testInfo.socketKeepaliveCallback).onPaused();
+
+        mNai.linkProperties.clear();
+
+        clearInvocations(mNai);
+        doResumeKeepalive(getAutoKiForBinder(testInfo.binder));
+        verify(mNai, never()).onStartNattSocketKeepalive(anyInt(), anyInt(), any());
+        verify(mNai, never()).onAddNattKeepalivePacketFilter(anyInt(), any());
+
+        assertNull(getAutoKiForBinder(testInfo.binder));
+
+        verify(testInfo.socketKeepaliveCallback).onError(SocketKeepalive.ERROR_INVALID_IP_ADDRESS);
+        verifyNoMoreInteractions(ignoreStubs(testInfo.socketKeepaliveCallback));
+    }
+
+    @Test
+    public void testResumeKeepalive_startingFailureHardwareError() throws Exception {
+        // Successful start of NATT keepalive.
+        final TestKeepaliveInfo testInfo = doStartNattKeepalive();
+        checkAndProcessKeepaliveStart(testInfo.kpd);
+        verify(testInfo.socketKeepaliveCallback).onStarted();
+
+        doPauseKeepalive(getAutoKiForBinder(testInfo.binder));
+        checkAndProcessKeepaliveStop();
+        verify(testInfo.socketKeepaliveCallback).onPaused();
+
+        clearInvocations(mNai);
+        doResumeKeepalive(getAutoKiForBinder(testInfo.binder));
+
+        verify(mNai)
+                .onStartNattSocketKeepalive(TEST_SLOT, TEST_KEEPALIVE_INTERVAL_SEC, testInfo.kpd);
+        verify(mNai).onAddNattKeepalivePacketFilter(TEST_SLOT, testInfo.kpd);
+        // Network agent returns error on starting the keepalive.
+        triggerEventKeepalive(TEST_SLOT, SocketKeepalive.ERROR_HARDWARE_ERROR);
+
+        checkAndProcessKeepaliveStop();
+
+        assertNull(getAutoKiForBinder(testInfo.binder));
+        verify(testInfo.socketKeepaliveCallback).onError(SocketKeepalive.ERROR_HARDWARE_ERROR);
+        verifyNoMoreInteractions(ignoreStubs(testInfo.socketKeepaliveCallback));
+    }
+
+    @Test
+    public void testStopAllKeepalives() throws Exception {
+        final TestKeepaliveInfo testInfo1 = doStartNattKeepalive();
+        final TestKeepaliveInfo testInfo2 = doStartNattKeepalive();
+        checkAndProcessKeepaliveStart(TEST_SLOT, testInfo1.kpd);
+        checkAndProcessKeepaliveStart(TEST_SLOT + 1, testInfo2.kpd);
+
+        verify(testInfo1.socketKeepaliveCallback).onStarted();
+        verify(testInfo2.socketKeepaliveCallback).onStarted();
+
+        // Pause the first keepalive
+        doPauseKeepalive(getAutoKiForBinder(testInfo1.binder));
+        checkAndProcessKeepaliveStop(TEST_SLOT);
+        verify(testInfo1.socketKeepaliveCallback).onPaused();
+
+        visibleOnHandlerThread(
+                mTestHandler,
+                () -> mAOOKeepaliveTracker.handleStopAllKeepalives(
+                        mNai, SocketKeepalive.ERROR_INVALID_NETWORK));
+
+        // Note that checkAndProcessKeepaliveStop is not called since the network agent is assumed
+        // to be disconnected for a handleStopAllKeepalives call.
+        assertNull(getAutoKiForBinder(testInfo1.binder));
+        assertNull(getAutoKiForBinder(testInfo2.binder));
+
+        verify(testInfo1.socketKeepaliveCallback, never()).onStopped();
+        verify(testInfo2.socketKeepaliveCallback, never()).onStopped();
+        verify(testInfo1.socketKeepaliveCallback).onError(SocketKeepalive.ERROR_INVALID_NETWORK);
+        verify(testInfo2.socketKeepaliveCallback).onError(SocketKeepalive.ERROR_INVALID_NETWORK);
+
+        verifyNoMoreInteractions(ignoreStubs(testInfo1.socketKeepaliveCallback));
+        verifyNoMoreInteractions(ignoreStubs(testInfo2.socketKeepaliveCallback));
+    }
+
+    @Test
+    public void testTwoKeepalives_startAfterPause() throws Exception {
+        final TestKeepaliveInfo testInfo1 = doStartNattKeepalive();
+        checkAndProcessKeepaliveStart(testInfo1.kpd);
+        verify(testInfo1.socketKeepaliveCallback).onStarted();
+        assertNotNull(getAutoKiForBinder(testInfo1.binder));
+
+        final AutomaticOnOffKeepalive autoKi1  = getAutoKiForBinder(testInfo1.binder);
+        doPauseKeepalive(autoKi1);
+        checkAndProcessKeepaliveStop(TEST_SLOT);
+        verify(testInfo1.socketKeepaliveCallback).onPaused();
+        assertNotNull(getAutoKiForBinder(testInfo1.binder));
+
+        clearInvocations(mNai);
+        // Start the second keepalive while the first is paused.
+        final TestKeepaliveInfo testInfo2 = doStartNattKeepalive();
+        // The slot used is TEST_SLOT since it is now a free slot.
+        checkAndProcessKeepaliveStart(TEST_SLOT, testInfo2.kpd);
+        verify(testInfo2.socketKeepaliveCallback).onStarted();
+        assertNotNull(getAutoKiForBinder(testInfo2.binder));
+
+        clearInvocations(mNai);
+        doResumeKeepalive(autoKi1);
+        // The next free slot is TEST_SLOT + 1.
+        checkAndProcessKeepaliveStart(TEST_SLOT + 1, testInfo1.kpd);
+        verify(testInfo1.socketKeepaliveCallback).onResumed();
+
+        clearInvocations(mNai);
+        doStopKeepalive(autoKi1);
+        // TODO: The slot should be consistent with the checkAndProcessKeepaliveStart directly above
+        checkAndProcessKeepaliveStop(TEST_SLOT);
+        // TODO: onStopped should only be called on the first keepalive callback.
+        verify(testInfo1.socketKeepaliveCallback, never()).onStopped();
+        verify(testInfo2.socketKeepaliveCallback).onStopped();
+        assertNull(getAutoKiForBinder(testInfo1.binder));
+
+        clearInvocations(mNai);
+        assertNotNull(getAutoKiForBinder(testInfo2.binder));
+        doStopKeepalive(getAutoKiForBinder(testInfo2.binder));
+        // This slot should be consistent with its corresponding checkAndProcessKeepaliveStart.
+        // TODO: checkAndProcessKeepaliveStop should be called instead but the keepalive is
+        // unexpectedly already stopped above.
+        verify(mNai, never()).onStopSocketKeepalive(TEST_SLOT);
+        verify(mNai, never()).onRemoveKeepalivePacketFilter(TEST_SLOT);
+
+        verify(testInfo2.socketKeepaliveCallback).onStopped();
+        assertNull(getAutoKiForBinder(testInfo2.binder));
+
+        verifyNoMoreInteractions(ignoreStubs(testInfo1.socketKeepaliveCallback));
+        verifyNoMoreInteractions(ignoreStubs(testInfo2.socketKeepaliveCallback));
+    }
 }