diff --git a/services/core/java/com/android/server/connectivity/Nat464Xlat.java b/services/core/java/com/android/server/connectivity/Nat464Xlat.java
index 34d0bed..3091a71 100644
--- a/services/core/java/com/android/server/connectivity/Nat464Xlat.java
+++ b/services/core/java/com/android/server/connectivity/Nat464Xlat.java
@@ -198,6 +198,9 @@
         if (mPrefixDiscoveryRunning && !isPrefixDiscoveryNeeded()) {
             stopPrefixDiscovery();
         }
+        if (!mPrefixDiscoveryRunning) {
+            setPrefix64(mNat64PrefixInUse);
+        }
     }
 
     /**
@@ -221,6 +224,10 @@
         mIface = null;
         mBaseIface = null;
 
+        if (!mPrefixDiscoveryRunning) {
+            setPrefix64(null);
+        }
+
         if (isPrefixDiscoveryNeeded()) {
             if (!mPrefixDiscoveryRunning) {
                 startPrefixDiscovery();
@@ -308,6 +315,16 @@
         return requiresClat(mNetwork) && mNat64PrefixFromRa == null;
     }
 
+    private void setPrefix64(IpPrefix prefix) {
+        final String prefixString = (prefix != null) ? prefix.toString() : "";
+        try {
+            mDnsResolver.setPrefix64(getNetId(), prefixString);
+        } catch (RemoteException | ServiceSpecificException e) {
+            Slog.e(TAG, "Error setting NAT64 prefix on netId " + getNetId() + " to "
+                    + prefix + ": " + e);
+        }
+    }
+
     private void maybeHandleNat64PrefixChange() {
         final IpPrefix newPrefix = selectNat64Prefix();
         if (!Objects.equals(mNat64PrefixInUse, newPrefix)) {
diff --git a/tests/net/java/com/android/server/ConnectivityServiceTest.java b/tests/net/java/com/android/server/ConnectivityServiceTest.java
index 83ca9b2..c86d388 100644
--- a/tests/net/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/net/java/com/android/server/ConnectivityServiceTest.java
@@ -6314,6 +6314,7 @@
         int netId = network.getNetId();
         callback.expectAvailableCallbacksUnvalidated(mCellNetworkAgent);
         inOrder.verify(mMockNetd).clatdStart(iface, pref64FromRa.toString());
+        inOrder.verify(mMockDnsResolver).setPrefix64(netId, pref64FromRa.toString());
         inOrder.verify(mMockDnsResolver, never()).startPrefix64Discovery(netId);
         callback.assertNoCallback();
         assertEquals(pref64FromRa, mCm.getLinkProperties(network).getNat64Prefix());
@@ -6323,6 +6324,7 @@
         mCellNetworkAgent.sendLinkProperties(lp);
         expectNat64PrefixChange(callback, mCellNetworkAgent, null);
         inOrder.verify(mMockNetd).clatdStop(iface);
+        inOrder.verify(mMockDnsResolver).setPrefix64(netId, "");
         inOrder.verify(mMockDnsResolver).startPrefix64Discovery(netId);
 
         // If the RA prefix appears while DNS discovery is in progress, discovery is stopped and
@@ -6332,6 +6334,7 @@
         expectNat64PrefixChange(callback, mCellNetworkAgent, pref64FromRa);
         inOrder.verify(mMockNetd).clatdStart(iface, pref64FromRa.toString());
         inOrder.verify(mMockDnsResolver).stopPrefix64Discovery(netId);
+        inOrder.verify(mMockDnsResolver).setPrefix64(netId, pref64FromRa.toString());
 
         // Withdraw the RA prefix so we can test the case where an RA prefix appears after DNS
         // discovery has succeeded.
@@ -6339,6 +6342,7 @@
         mCellNetworkAgent.sendLinkProperties(lp);
         expectNat64PrefixChange(callback, mCellNetworkAgent, null);
         inOrder.verify(mMockNetd).clatdStop(iface);
+        inOrder.verify(mMockDnsResolver).setPrefix64(netId, "");
         inOrder.verify(mMockDnsResolver).startPrefix64Discovery(netId);
 
         mService.mNetdEventCallback.onNat64PrefixEvent(netId, true /* added */,
@@ -6346,13 +6350,40 @@
         expectNat64PrefixChange(callback, mCellNetworkAgent, pref64FromDns);
         inOrder.verify(mMockNetd).clatdStart(iface, pref64FromDns.toString());
 
-        // If the RA prefix reappears, clatd is restarted and prefix discovery is stopped.
+        // If an RA advertises the same prefix that was discovered by DNS, nothing happens: prefix
+        // discovery is not stopped, and there are no callbacks.
+        lp.setNat64Prefix(pref64FromDns);
+        mCellNetworkAgent.sendLinkProperties(lp);
+        callback.assertNoCallback();
+        inOrder.verify(mMockNetd, never()).clatdStop(iface);
+        inOrder.verify(mMockNetd, never()).clatdStart(eq(iface), anyString());
+        inOrder.verify(mMockDnsResolver, never()).stopPrefix64Discovery(netId);
+        inOrder.verify(mMockDnsResolver, never()).startPrefix64Discovery(netId);
+        inOrder.verify(mMockDnsResolver, never()).setPrefix64(eq(netId), anyString());
+
+        // If the RA is later withdrawn, nothing happens again.
+        lp.setNat64Prefix(null);
+        mCellNetworkAgent.sendLinkProperties(lp);
+        callback.assertNoCallback();
+        inOrder.verify(mMockNetd, never()).clatdStop(iface);
+        inOrder.verify(mMockNetd, never()).clatdStart(eq(iface), anyString());
+        inOrder.verify(mMockDnsResolver, never()).stopPrefix64Discovery(netId);
+        inOrder.verify(mMockDnsResolver, never()).startPrefix64Discovery(netId);
+        inOrder.verify(mMockDnsResolver, never()).setPrefix64(eq(netId), anyString());
+
+        // If the RA prefix changes, clatd is restarted and prefix discovery is stopped.
         lp.setNat64Prefix(pref64FromRa);
         mCellNetworkAgent.sendLinkProperties(lp);
         expectNat64PrefixChange(callback, mCellNetworkAgent, pref64FromRa);
         inOrder.verify(mMockNetd).clatdStop(iface);
         inOrder.verify(mMockDnsResolver).stopPrefix64Discovery(netId);
+
+        // Stopping prefix discovery results in a prefix removed notification.
+        mService.mNetdEventCallback.onNat64PrefixEvent(netId, false /* added */,
+                pref64FromDnsStr, 96);
+
         inOrder.verify(mMockNetd).clatdStart(iface, pref64FromRa.toString());
+        inOrder.verify(mMockDnsResolver).setPrefix64(netId, pref64FromRa.toString());
         inOrder.verify(mMockDnsResolver, never()).startPrefix64Discovery(netId);
 
         // If the RA prefix changes, clatd is restarted and prefix discovery is not started.
@@ -6360,7 +6391,9 @@
         mCellNetworkAgent.sendLinkProperties(lp);
         expectNat64PrefixChange(callback, mCellNetworkAgent, newPref64FromRa);
         inOrder.verify(mMockNetd).clatdStop(iface);
+        inOrder.verify(mMockDnsResolver).setPrefix64(netId, "");
         inOrder.verify(mMockNetd).clatdStart(iface, newPref64FromRa.toString());
+        inOrder.verify(mMockDnsResolver).setPrefix64(netId, newPref64FromRa.toString());
         inOrder.verify(mMockDnsResolver, never()).stopPrefix64Discovery(netId);
         inOrder.verify(mMockDnsResolver, never()).startPrefix64Discovery(netId);
 
@@ -6373,11 +6406,45 @@
         inOrder.verify(mMockNetd, never()).clatdStart(eq(iface), anyString());
         inOrder.verify(mMockDnsResolver, never()).stopPrefix64Discovery(netId);
         inOrder.verify(mMockDnsResolver, never()).startPrefix64Discovery(netId);
+        inOrder.verify(mMockDnsResolver, never()).setPrefix64(eq(netId), anyString());
 
         // The transition between no prefix and DNS prefix is tested in testStackedLinkProperties.
 
+        // If the same prefix is learned first by DNS and then by RA, and clat is later stopped,
+        // (e.g., because the network disconnects) setPrefix64(netid, "") is never called.
+        lp.setNat64Prefix(null);
+        mCellNetworkAgent.sendLinkProperties(lp);
+        expectNat64PrefixChange(callback, mCellNetworkAgent, null);
+        inOrder.verify(mMockNetd).clatdStop(iface);
+        inOrder.verify(mMockDnsResolver).setPrefix64(netId, "");
+        inOrder.verify(mMockDnsResolver).startPrefix64Discovery(netId);
+        mService.mNetdEventCallback.onNat64PrefixEvent(netId, true /* added */,
+                pref64FromDnsStr, 96);
+        expectNat64PrefixChange(callback, mCellNetworkAgent, pref64FromDns);
+        inOrder.verify(mMockNetd).clatdStart(iface, pref64FromDns.toString());
+        inOrder.verify(mMockDnsResolver, never()).setPrefix64(eq(netId), any());
+
+        lp.setNat64Prefix(pref64FromDns);
+        mCellNetworkAgent.sendLinkProperties(lp);
         callback.assertNoCallback();
+        inOrder.verify(mMockNetd, never()).clatdStop(iface);
+        inOrder.verify(mMockNetd, never()).clatdStart(eq(iface), anyString());
+        inOrder.verify(mMockDnsResolver, never()).stopPrefix64Discovery(netId);
+        inOrder.verify(mMockDnsResolver, never()).startPrefix64Discovery(netId);
+        inOrder.verify(mMockDnsResolver, never()).setPrefix64(eq(netId), anyString());
+
+        // When tearing down a network, clat state is only updated after CALLBACK_LOST is fired, but
+        // before CONNECTIVITY_ACTION is sent. Wait for CONNECTIVITY_ACTION before verifying that
+        // clat has been stopped, or the test will be flaky.
+        ConditionVariable cv = registerConnectivityBroadcast(1);
         mCellNetworkAgent.disconnect();
+        callback.expectCallback(CallbackEntry.LOST, mCellNetworkAgent);
+        waitFor(cv);
+
+        inOrder.verify(mMockNetd).clatdStop(iface);
+        inOrder.verify(mMockDnsResolver).stopPrefix64Discovery(netId);
+        inOrder.verify(mMockDnsResolver, never()).setPrefix64(eq(netId), anyString());
+
         mCm.unregisterNetworkCallback(callback);
     }