diff --git a/framework/src/android/net/ConnectivityManager.java b/framework/src/android/net/ConnectivityManager.java
index d04a5be..0976b75 100644
--- a/framework/src/android/net/ConnectivityManager.java
+++ b/framework/src/android/net/ConnectivityManager.java
@@ -21,6 +21,7 @@
 import static android.net.NetworkRequest.Type.LISTEN;
 import static android.net.NetworkRequest.Type.REQUEST;
 import static android.net.NetworkRequest.Type.TRACK_DEFAULT;
+import static android.net.NetworkRequest.Type.TRACK_SYSTEM_DEFAULT;
 import static android.net.QosCallback.QosCallbackRegistrationException;
 
 import android.annotation.CallbackExecutor;
@@ -3721,7 +3722,8 @@
         printStackTrace();
         checkCallbackNotNull(callback);
         Preconditions.checkArgument(
-                reqType == TRACK_DEFAULT || need != null, "null NetworkCapabilities");
+                reqType == TRACK_DEFAULT || reqType == TRACK_SYSTEM_DEFAULT || need != null,
+                "null NetworkCapabilities");
         final NetworkRequest request;
         final String callingPackageName = mContext.getOpPackageName();
         try {
@@ -4192,8 +4194,9 @@
     }
 
     /**
-     * Registers to receive notifications about changes in the system default network. The callbacks
-     * will continue to be called until either the application exits or
+     * Registers to receive notifications about changes in the application's default network. This
+     * may be a physical network or a virtual network, such as a VPN that applies to the
+     * application. The callbacks will continue to be called until either the application exits or
      * {@link #unregisterNetworkCallback(NetworkCallback)} is called.
      *
      * <p>To avoid performance issues due to apps leaking callbacks, the system will limit the
@@ -4206,7 +4209,7 @@
      * {@link #unregisterNetworkCallback(NetworkCallback)}.
      *
      * @param networkCallback The {@link NetworkCallback} that the system will call as the
-     *                        system default network changes.
+     *                        application's default network changes.
      *                        The callback is invoked on the default internal Handler.
      * @throws RuntimeException if the app already has too many callbacks registered.
      */
@@ -4216,10 +4219,46 @@
     }
 
     /**
+     * Registers to receive notifications about changes in the application's default network. This
+     * may be a physical network or a virtual network, such as a VPN that applies to the
+     * application. The callbacks will continue to be called until either the application exits or
+     * {@link #unregisterNetworkCallback(NetworkCallback)} is called.
+     *
+     * <p>To avoid performance issues due to apps leaking callbacks, the system will limit the
+     * number of outstanding requests to 100 per app (identified by their UID), shared with
+     * all variants of this method, of {@link #requestNetwork} as well as
+     * {@link ConnectivityDiagnosticsManager#registerConnectivityDiagnosticsCallback}.
+     * Requesting a network with this method will count toward this limit. If this limit is
+     * exceeded, an exception will be thrown. To avoid hitting this issue and to conserve resources,
+     * make sure to unregister the callbacks with
+     * {@link #unregisterNetworkCallback(NetworkCallback)}.
+     *
+     * @param networkCallback The {@link NetworkCallback} that the system will call as the
+     *                        application's default network changes.
+     * @param handler {@link Handler} to specify the thread upon which the callback will be invoked.
+     * @throws RuntimeException if the app already has too many callbacks registered.
+     */
+    @RequiresPermission(android.Manifest.permission.ACCESS_NETWORK_STATE)
+    public void registerDefaultNetworkCallback(@NonNull NetworkCallback networkCallback,
+            @NonNull Handler handler) {
+        CallbackHandler cbHandler = new CallbackHandler(handler);
+        sendRequestForNetwork(null /* NetworkCapabilities need */, networkCallback, 0,
+                TRACK_DEFAULT, TYPE_NONE, cbHandler);
+    }
+
+    /**
      * Registers to receive notifications about changes in the system default network. The callbacks
      * will continue to be called until either the application exits or
      * {@link #unregisterNetworkCallback(NetworkCallback)} is called.
      *
+     * This method should not be used to determine networking state seen by applications, because in
+     * many cases, most or even all application traffic may not use the default network directly,
+     * and traffic from different applications may go on different networks by default. As an
+     * example, if a VPN is connected, traffic from all applications might be sent through the VPN
+     * and not onto the system default network. Applications or system components desiring to do
+     * determine network state as seen by applications should use other methods such as
+     * {@link #registerDefaultNetworkCallback(NetworkCallback, Handler)}.
+     *
      * <p>To avoid performance issues due to apps leaking callbacks, the system will limit the
      * number of outstanding requests to 100 per app (identified by their UID), shared with
      * all variants of this method, of {@link #requestNetwork} as well as
@@ -4233,20 +4272,19 @@
      *                        system default network changes.
      * @param handler {@link Handler} to specify the thread upon which the callback will be invoked.
      * @throws RuntimeException if the app already has too many callbacks registered.
+     *
+     * @hide
      */
-    @RequiresPermission(android.Manifest.permission.ACCESS_NETWORK_STATE)
-    public void registerDefaultNetworkCallback(@NonNull NetworkCallback networkCallback,
+    @SystemApi(client = MODULE_LIBRARIES)
+    @SuppressLint({"ExecutorRegistration", "PairedRegistration"})
+    @RequiresPermission(anyOf = {
+            NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK,
+            android.Manifest.permission.NETWORK_SETTINGS})
+    public void registerSystemDefaultNetworkCallback(@NonNull NetworkCallback networkCallback,
             @NonNull Handler handler) {
-        // This works because if the NetworkCapabilities are null,
-        // ConnectivityService takes them from the default request.
-        //
-        // Since the capabilities are exactly the same as the default request's
-        // capabilities, this request is guaranteed, at all times, to be
-        // satisfied by the same network, if any, that satisfies the default
-        // request, i.e., the system default network.
         CallbackHandler cbHandler = new CallbackHandler(handler);
         sendRequestForNetwork(null /* NetworkCapabilities need */, networkCallback, 0,
-                TRACK_DEFAULT, TYPE_NONE, cbHandler);
+                TRACK_SYSTEM_DEFAULT, TYPE_NONE, cbHandler);
     }
 
     /**
diff --git a/framework/src/android/net/NetworkRequest.java b/framework/src/android/net/NetworkRequest.java
index 6540397..b4a651c 100644
--- a/framework/src/android/net/NetworkRequest.java
+++ b/framework/src/android/net/NetworkRequest.java
@@ -104,17 +104,14 @@
      *       callbacks about the single, highest scoring current network
      *       (if any) that matches the specified NetworkCapabilities, or
      *
-     *     - TRACK_DEFAULT, a hybrid of the two designed such that the
-     *       framework will issue callbacks for the single, highest scoring
-     *       current network (if any) that matches the capabilities of the
-     *       default Internet request (mDefaultRequest), but which cannot cause
-     *       the framework to either create or retain the existence of any
-     *       specific network. Note that from the point of view of the request
-     *       matching code, TRACK_DEFAULT is identical to REQUEST: its special
-     *       behaviour is not due to different semantics, but to the fact that
-     *       the system will only ever create a TRACK_DEFAULT with capabilities
-     *       that are identical to the default request's capabilities, thus
-     *       causing it to share fate in every way with the default request.
+     *     - TRACK_DEFAULT, which causes the framework to issue callbacks for
+     *       the single, highest scoring current network (if any) that will
+     *       be chosen for an app, but which cannot cause the framework to
+     *       either create or retain the existence of any specific network.
+     *
+     *     - TRACK_SYSTEM_DEFAULT, which causes the framework to send callbacks
+     *       for the network (if any) that satisfies the default Internet
+     *       request.
      *
      *     - BACKGROUND_REQUEST, like REQUEST but does not cause any networks
      *       to retain the NET_CAPABILITY_FOREGROUND capability. A network with
@@ -137,6 +134,7 @@
         TRACK_DEFAULT,
         REQUEST,
         BACKGROUND_REQUEST,
+        TRACK_SYSTEM_DEFAULT,
     };
 
     /**
@@ -601,6 +599,8 @@
                 return NetworkRequestProto.TYPE_REQUEST;
             case BACKGROUND_REQUEST:
                 return NetworkRequestProto.TYPE_BACKGROUND_REQUEST;
+            case TRACK_SYSTEM_DEFAULT:
+                return NetworkRequestProto.TYPE_TRACK_SYSTEM_DEFAULT;
             default:
                 return NetworkRequestProto.TYPE_UNKNOWN;
         }
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index 06f9358..5164437 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -5746,6 +5746,7 @@
                 throw new SecurityException("Insufficient permissions to specify legacy type");
             }
         }
+        final NetworkCapabilities defaultNc = mDefaultRequest.mRequests.get(0).networkCapabilities;
         final int callingUid = mDeps.getCallingUid();
         final NetworkRequest.Type reqType;
         try {
@@ -5756,11 +5757,15 @@
         switch (reqType) {
             case TRACK_DEFAULT:
                 // If the request type is TRACK_DEFAULT, the passed {@code networkCapabilities}
-                // is unused and will be replaced by the one from the default network request.
-                // This allows callers to keep track of the system default network.
+                // is unused and will be replaced by ones appropriate for the caller.
+                // This allows callers to keep track of the default network for their app.
                 networkCapabilities = createDefaultNetworkCapabilitiesForUid(callingUid);
                 enforceAccessPermission();
                 break;
+            case TRACK_SYSTEM_DEFAULT:
+                enforceSettingsPermission();
+                networkCapabilities = new NetworkCapabilities(defaultNc);
+                break;
             case BACKGROUND_REQUEST:
                 enforceNetworkStackOrSettingsPermission();
                 // Fall-through since other checks are the same with normal requests.
@@ -5779,6 +5784,7 @@
         ensureRequestableCapabilities(networkCapabilities);
         ensureSufficientPermissionsForRequest(networkCapabilities,
                 Binder.getCallingPid(), callingUid, callingPackageName);
+
         // Set the UID range for this request to the single UID of the requester, or to an empty
         // set of UIDs if the caller has the appropriate permission and UIDs have not been set.
         // This will overwrite any allowed UIDs in the requested capabilities. Though there
@@ -5798,6 +5804,16 @@
                 new NetworkRequestInfo(messenger, networkRequest, binder, callingAttributionTag);
         if (DBG) log("requestNetwork for " + nri);
 
+        // For TRACK_SYSTEM_DEFAULT callbacks, the capabilities have been modified since they were
+        // copied from the default request above. (This is necessary to ensure, for example, that
+        // the callback does not leak sensitive information to unprivileged apps.) Check that the
+        // changes don't alter request matching.
+        if (reqType == NetworkRequest.Type.TRACK_SYSTEM_DEFAULT &&
+                (!networkCapabilities.equalRequestableCapabilities(defaultNc))) {
+            Log.wtf(TAG, "TRACK_SYSTEM_DEFAULT capabilities don't match default request: "
+                    + networkCapabilities + " vs. " + defaultNc);
+        }
+
         mHandler.sendMessage(mHandler.obtainMessage(EVENT_REGISTER_NETWORK_REQUEST, nri));
         if (timeoutMs > 0) {
             mHandler.sendMessageDelayed(mHandler.obtainMessage(EVENT_TIMEOUT_NETWORK_REQUEST,
diff --git a/services/core/java/com/android/server/connectivity/NetworkAgentInfo.java b/services/core/java/com/android/server/connectivity/NetworkAgentInfo.java
index bff1a5c..c05e253 100644
--- a/services/core/java/com/android/server/connectivity/NetworkAgentInfo.java
+++ b/services/core/java/com/android/server/connectivity/NetworkAgentInfo.java
@@ -717,8 +717,9 @@
                 mNumBackgroundNetworkRequests += delta;
                 break;
 
-            case TRACK_DEFAULT:
             case LISTEN:
+            case TRACK_DEFAULT:
+            case TRACK_SYSTEM_DEFAULT:
                 break;
 
             case NONE:
diff --git a/tests/net/java/android/net/ConnectivityManagerTest.java b/tests/net/java/android/net/ConnectivityManagerTest.java
index fcfb4aa..6a09b02 100644
--- a/tests/net/java/android/net/ConnectivityManagerTest.java
+++ b/tests/net/java/android/net/ConnectivityManagerTest.java
@@ -35,6 +35,7 @@
 import static android.net.NetworkRequest.Type.BACKGROUND_REQUEST;
 import static android.net.NetworkRequest.Type.REQUEST;
 import static android.net.NetworkRequest.Type.TRACK_DEFAULT;
+import static android.net.NetworkRequest.Type.TRACK_SYSTEM_DEFAULT;
 
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
@@ -329,6 +330,9 @@
         mustFail(() -> { manager.registerDefaultNetworkCallback(null, handler); });
         mustFail(() -> { manager.registerDefaultNetworkCallback(callback, null); });
 
+        mustFail(() -> { manager.registerSystemDefaultNetworkCallback(null, handler); });
+        mustFail(() -> { manager.registerSystemDefaultNetworkCallback(callback, null); });
+
         mustFail(() -> { manager.unregisterNetworkCallback(nullCallback); });
         mustFail(() -> { manager.unregisterNetworkCallback(nullIntent); });
         mustFail(() -> { manager.releaseNetworkRequest(nullIntent); });
@@ -377,6 +381,13 @@
                 eq(BACKGROUND_REQUEST.ordinal()), any(), anyInt(), any(), eq(TYPE_NONE),
                 eq(testPkgName), eq(testAttributionTag));
         reset(mService);
+
+        Handler handler = new Handler(ConnectivityThread.getInstanceLooper());
+        manager.registerSystemDefaultNetworkCallback(callback, handler);
+        verify(mService).requestNetwork(eq(null),
+                eq(TRACK_SYSTEM_DEFAULT.ordinal()), any(), anyInt(), any(), eq(TYPE_NONE),
+                eq(testPkgName), eq(testAttributionTag));
+        reset(mService);
     }
 
     static Message makeMessage(NetworkRequest req, int messageType) {
diff --git a/tests/net/java/com/android/server/ConnectivityServiceTest.java b/tests/net/java/com/android/server/ConnectivityServiceTest.java
index edc2c63..ecdc621 100644
--- a/tests/net/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/net/java/com/android/server/ConnectivityServiceTest.java
@@ -3649,10 +3649,19 @@
 
     @Test
     public void testRegisterDefaultNetworkCallback() throws Exception {
+        // NETWORK_SETTINGS is necessary to call registerSystemDefaultNetworkCallback.
+        mServiceContext.setPermission(Manifest.permission.NETWORK_SETTINGS,
+                PERMISSION_GRANTED);
+
         final TestNetworkCallback defaultNetworkCallback = new TestNetworkCallback();
         mCm.registerDefaultNetworkCallback(defaultNetworkCallback);
         defaultNetworkCallback.assertNoCallback();
 
+        final Handler handler = new Handler(ConnectivityThread.getInstanceLooper());
+        final TestNetworkCallback systemDefaultCallback = new TestNetworkCallback();
+        mCm.registerSystemDefaultNetworkCallback(systemDefaultCallback, handler);
+        systemDefaultCallback.assertNoCallback();
+
         // Create a TRANSPORT_CELLULAR request to keep the mobile interface up
         // whenever Wi-Fi is up. Without this, the mobile network agent is
         // reaped before any other activity can take place.
@@ -3667,27 +3676,35 @@
         mCellNetworkAgent.connect(true);
         cellNetworkCallback.expectAvailableThenValidatedCallbacks(mCellNetworkAgent);
         defaultNetworkCallback.expectAvailableThenValidatedCallbacks(mCellNetworkAgent);
+        systemDefaultCallback.expectAvailableThenValidatedCallbacks(mCellNetworkAgent);
         assertEquals(defaultNetworkCallback.getLastAvailableNetwork(), mCm.getActiveNetwork());
+        assertEquals(systemDefaultCallback.getLastAvailableNetwork(), mCm.getActiveNetwork());
 
         // Bring up wifi and expect CALLBACK_AVAILABLE.
         mWiFiNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_WIFI);
         mWiFiNetworkAgent.connect(true);
         cellNetworkCallback.assertNoCallback();
         defaultNetworkCallback.expectAvailableDoubleValidatedCallbacks(mWiFiNetworkAgent);
+        systemDefaultCallback.expectAvailableDoubleValidatedCallbacks(mWiFiNetworkAgent);
         assertEquals(defaultNetworkCallback.getLastAvailableNetwork(), mCm.getActiveNetwork());
+        assertEquals(systemDefaultCallback.getLastAvailableNetwork(), mCm.getActiveNetwork());
 
         // Bring down cell. Expect no default network callback, since it wasn't the default.
         mCellNetworkAgent.disconnect();
         cellNetworkCallback.expectCallback(CallbackEntry.LOST, mCellNetworkAgent);
         defaultNetworkCallback.assertNoCallback();
+        systemDefaultCallback.assertNoCallback();
         assertEquals(defaultNetworkCallback.getLastAvailableNetwork(), mCm.getActiveNetwork());
+        assertEquals(systemDefaultCallback.getLastAvailableNetwork(), mCm.getActiveNetwork());
 
         // Bring up cell. Expect no default network callback, since it won't be the default.
         mCellNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_CELLULAR);
         mCellNetworkAgent.connect(true);
         cellNetworkCallback.expectAvailableThenValidatedCallbacks(mCellNetworkAgent);
         defaultNetworkCallback.assertNoCallback();
+        systemDefaultCallback.assertNoCallback();
         assertEquals(defaultNetworkCallback.getLastAvailableNetwork(), mCm.getActiveNetwork());
+        assertEquals(systemDefaultCallback.getLastAvailableNetwork(), mCm.getActiveNetwork());
 
         // Bring down wifi. Expect the default network callback to notified of LOST wifi
         // followed by AVAILABLE cell.
@@ -3695,19 +3712,25 @@
         cellNetworkCallback.assertNoCallback();
         defaultNetworkCallback.expectCallback(CallbackEntry.LOST, mWiFiNetworkAgent);
         defaultNetworkCallback.expectAvailableCallbacksValidated(mCellNetworkAgent);
+        systemDefaultCallback.expectCallback(CallbackEntry.LOST, mWiFiNetworkAgent);
+        systemDefaultCallback.expectAvailableCallbacksValidated(mCellNetworkAgent);
         mCellNetworkAgent.disconnect();
         cellNetworkCallback.expectCallback(CallbackEntry.LOST, mCellNetworkAgent);
         defaultNetworkCallback.expectCallback(CallbackEntry.LOST, mCellNetworkAgent);
+        systemDefaultCallback.expectCallback(CallbackEntry.LOST, mCellNetworkAgent);
         waitForIdle();
         assertEquals(null, mCm.getActiveNetwork());
 
         mMockVpn.establishForMyUid();
         assertUidRangesUpdatedForMyUid(true);
         defaultNetworkCallback.expectAvailableThenValidatedCallbacks(mMockVpn);
+        systemDefaultCallback.assertNoCallback();
         assertEquals(defaultNetworkCallback.getLastAvailableNetwork(), mCm.getActiveNetwork());
+        assertEquals(null, systemDefaultCallback.getLastAvailableNetwork());
 
         mMockVpn.disconnect();
         defaultNetworkCallback.expectCallback(CallbackEntry.LOST, mMockVpn);
+        systemDefaultCallback.assertNoCallback();
         waitForIdle();
         assertEquals(null, mCm.getActiveNetwork());
     }
@@ -6134,6 +6157,10 @@
 
     @Test
     public void testVpnNetworkActive() throws Exception {
+        // NETWORK_SETTINGS is necessary to call registerSystemDefaultNetworkCallback.
+        mServiceContext.setPermission(Manifest.permission.NETWORK_SETTINGS,
+                PERMISSION_GRANTED);
+
         final int uid = Process.myUid();
 
         final TestNetworkCallback genericNetworkCallback = new TestNetworkCallback();
@@ -6141,6 +6168,7 @@
         final TestNetworkCallback wifiNetworkCallback = new TestNetworkCallback();
         final TestNetworkCallback vpnNetworkCallback = new TestNetworkCallback();
         final TestNetworkCallback defaultCallback = new TestNetworkCallback();
+        final TestNetworkCallback systemDefaultCallback = new TestNetworkCallback();
         final NetworkRequest genericNotVpnRequest = new NetworkRequest.Builder().build();
         final NetworkRequest genericRequest = new NetworkRequest.Builder()
                 .removeCapability(NET_CAPABILITY_NOT_VPN).build();
@@ -6154,6 +6182,8 @@
         mCm.registerNetworkCallback(wifiRequest, wifiNetworkCallback);
         mCm.registerNetworkCallback(vpnNetworkRequest, vpnNetworkCallback);
         mCm.registerDefaultNetworkCallback(defaultCallback);
+        mCm.registerSystemDefaultNetworkCallback(systemDefaultCallback,
+                new Handler(ConnectivityThread.getInstanceLooper()));
         defaultCallback.assertNoCallback();
 
         mWiFiNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_WIFI);
@@ -6163,6 +6193,7 @@
         genericNotVpnNetworkCallback.expectAvailableCallbacksUnvalidated(mWiFiNetworkAgent);
         wifiNetworkCallback.expectAvailableCallbacksUnvalidated(mWiFiNetworkAgent);
         defaultCallback.expectAvailableCallbacksUnvalidated(mWiFiNetworkAgent);
+        systemDefaultCallback.expectAvailableCallbacksUnvalidated(mWiFiNetworkAgent);
         vpnNetworkCallback.assertNoCallback();
         assertEquals(defaultCallback.getLastAvailableNetwork(), mCm.getActiveNetwork());
 
@@ -6183,7 +6214,10 @@
         wifiNetworkCallback.assertNoCallback();
         vpnNetworkCallback.expectAvailableThenValidatedCallbacks(mMockVpn);
         defaultCallback.expectAvailableThenValidatedCallbacks(mMockVpn);
+        systemDefaultCallback.assertNoCallback();
         assertEquals(defaultCallback.getLastAvailableNetwork(), mCm.getActiveNetwork());
+        assertEquals(mWiFiNetworkAgent.getNetwork(),
+                systemDefaultCallback.getLastAvailableNetwork());
 
         ranges.clear();
         mMockVpn.setUids(ranges);
@@ -6200,6 +6234,7 @@
         // much, but that is the reason the test here has to check for an update to the
         // capabilities instead of the expected LOST then AVAILABLE.
         defaultCallback.expectCallback(CallbackEntry.NETWORK_CAPS_UPDATED, mMockVpn);
+        systemDefaultCallback.assertNoCallback();
 
         ranges.add(new UidRange(uid, uid));
         mMockVpn.setUids(ranges);
@@ -6211,6 +6246,7 @@
         // TODO : Here like above, AVAILABLE would be correct, but because this can't actually
         // happen outside of the test, ConnectivityService does not rematch callbacks.
         defaultCallback.expectCallback(CallbackEntry.NETWORK_CAPS_UPDATED, mMockVpn);
+        systemDefaultCallback.assertNoCallback();
 
         mWiFiNetworkAgent.disconnect();
 
@@ -6219,6 +6255,7 @@
         wifiNetworkCallback.expectCallback(CallbackEntry.LOST, mWiFiNetworkAgent);
         vpnNetworkCallback.assertNoCallback();
         defaultCallback.assertNoCallback();
+        systemDefaultCallback.expectCallback(CallbackEntry.LOST, mWiFiNetworkAgent);
 
         mMockVpn.disconnect();
 
@@ -6227,12 +6264,14 @@
         wifiNetworkCallback.assertNoCallback();
         vpnNetworkCallback.expectCallback(CallbackEntry.LOST, mMockVpn);
         defaultCallback.expectCallback(CallbackEntry.LOST, mMockVpn);
+        systemDefaultCallback.assertNoCallback();
         assertEquals(null, mCm.getActiveNetwork());
 
         mCm.unregisterNetworkCallback(genericNetworkCallback);
         mCm.unregisterNetworkCallback(wifiNetworkCallback);
         mCm.unregisterNetworkCallback(vpnNetworkCallback);
         mCm.unregisterNetworkCallback(defaultCallback);
+        mCm.unregisterNetworkCallback(systemDefaultCallback);
     }
 
     @Test