diff --git a/service/src/com/android/server/ConnectivityService.java b/service/src/com/android/server/ConnectivityService.java
index 05ea6f962f..529c51d6bd 100644
--- a/service/src/com/android/server/ConnectivityService.java
+++ b/service/src/com/android/server/ConnectivityService.java
@@ -2152,7 +2152,10 @@ public class ConnectivityService extends IConnectivityManager.Stub
 
         mL2capNetworkProvider = mDeps.makeL2capNetworkProvider(mContext);
 
-        mCloseQuicConnection = mDeps.isFeatureEnabled(context, CLOSE_QUIC_CONNECTION);
+        // QUIC connection close is triggered by freezer (U+) or background firewall chain (V+).
+        // TODO: Allow other firewall chains to close QUIC connection and enable this flag on T+
+        mCloseQuicConnection = mDeps.isAtLeastU()
+                && mDeps.isFeatureNotChickenedOut(context, CLOSE_QUIC_CONNECTION);
         if (mCloseQuicConnection) {
             mQuicConnectionCloser = mDeps.makeQuicConnectionCloser(mNetworkForNetId, mHandler);
         } else {
diff --git a/service/src/com/android/server/connectivity/QuicConnectionCloser.java b/service/src/com/android/server/connectivity/QuicConnectionCloser.java
index c582d60f4f..c4fe5b8621 100644
--- a/service/src/com/android/server/connectivity/QuicConnectionCloser.java
+++ b/service/src/com/android/server/connectivity/QuicConnectionCloser.java
@@ -254,8 +254,14 @@ public class QuicConnectionCloser {
 
         Log.d(TAG, "Close QUIC socket for " + info + ", destroySocket=" + destroySocket);
         final NetworkAgentInfo nai = getNetworkAgentInfoForNetId(info.netId);
-        if (nai == null || !nai.linkProperties.getAddresses().contains(info.src.getAddress())) {
+        if (nai == null) return; // The network has gone away already
+
+        final boolean isLoopbackConnection = info.dst.getAddress().isLoopbackAddress();
+        final boolean lpContainsSourceAddress =
+                nai.linkProperties.getAddresses().contains(info.src.getAddress());
+        if (!isLoopbackConnection && !lpContainsSourceAddress) {
             // The device should not send a packet with an unused source address.
+            // Loopback connections are closed exceptionally to simplify device local testing.
             return;
         }
 
diff --git a/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java b/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
index 3a3b256fc9..2ddaa50245 100644
--- a/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
+++ b/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
@@ -4358,8 +4358,11 @@ public class ConnectivityManagerTest {
         });
     }
 
+    // This test is skipped on U and older releases because QUIC connection close can be triggered
+    // by the freezer (U+) or the background firewall chain (V+), but the freezer cannot be tested.
+    // TODO: Enable this test on T+ once other firewall chains can trigger QUIC connection close.
     @Test
-    @IgnoreUpTo(Build.VERSION_CODES.R)
+    @IgnoreUpTo(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
     @ConnectivityModuleTest
     @AppModeFull(reason = "Cannot create test network in instant app mode")
     public void testRegisterQuicConnectionClosePayload_blockNetwork() throws Exception {
@@ -4384,8 +4387,9 @@ public class ConnectivityManagerTest {
                 true /* blockNetwork */, false /* expectPacketSent */);
     }
 
+    // TODO: Enable this test on T+ once other firewall chains can trigger QUIC connection close.
     @Test
-    @IgnoreUpTo(Build.VERSION_CODES.R)
+    @IgnoreUpTo(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
     @ConnectivityModuleTest
     @AppModeFull(reason = "Cannot create test network in instant app mode")
     public void testRegisterQuicConnectionClosePayload_closeSocket() throws Exception {
diff --git a/tests/unit/java/com/android/server/ConnectivityServiceTest.java b/tests/unit/java/com/android/server/ConnectivityServiceTest.java
index 7108d2dcf2..ce04e94d7c 100755
--- a/tests/unit/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/unit/java/com/android/server/ConnectivityServiceTest.java
@@ -2188,7 +2188,6 @@ public class ConnectivityServiceTest {
                 case ConnectivityFlags.USE_DECLARED_METHODS_FOR_CALLBACKS:
                 case ConnectivityFlags.QUEUE_CALLBACKS_FOR_FROZEN_APPS:
                 case ConnectivityFlags.BACKGROUND_FIREWALL_CHAIN:
-                case ConnectivityFlags.CLOSE_QUIC_CONNECTION:
                 case ConnectivityService.KEY_DESTROY_FROZEN_SOCKETS_VERSION:
                     return true;
                 default:
@@ -2209,6 +2208,7 @@ public class ConnectivityServiceTest {
                 case ConnectivityFlags.USE_DECLARED_METHODS_FOR_CALLBACKS:
                 case ConnectivityFlags.QUEUE_CALLBACKS_FOR_FROZEN_APPS:
                 case ConnectivityFlags.QUEUE_NETWORK_AGENT_EVENTS_IN_SYSTEM_SERVER:
+                case ConnectivityFlags.CLOSE_QUIC_CONNECTION:
                     return true;
                 default:
                     throw new UnsupportedOperationException("Unknown flag " + name