diff --git a/framework-t/src/android/net/IpSecManager.java b/framework-t/src/android/net/IpSecManager.java
index 9cb0947..9cceac2 100644
--- a/framework-t/src/android/net/IpSecManager.java
+++ b/framework-t/src/android/net/IpSecManager.java
@@ -817,10 +817,10 @@
          * </ol>
          *
          * @param underlyingNetwork the new {@link Network} that will carry traffic for this tunnel.
-         *     This network MUST never be the network exposing this IpSecTunnelInterface, otherwise
-         *     this method will throw an {@link IllegalArgumentException}. If the
-         *     IpSecTunnelInterface is later added to this network, all outbound traffic will be
-         *     blackholed.
+         *     This network MUST be a functional {@link Network} with valid {@link LinkProperties},
+         *     and MUST never be the network exposing this IpSecTunnelInterface, otherwise this
+         *     method will throw an {@link IllegalArgumentException}. If the IpSecTunnelInterface is
+         *     later added to this network, all outbound traffic will be blackholed.
          */
         // TODO: b/169171001 Update the documentation when transform migration is supported.
         // The purpose of making updating network and applying transforms separate is to leave open
@@ -962,7 +962,6 @@
      * IP header and IPsec Header on all inbound traffic).
      * <p>Applications should probably not use this API directly.
      *
-     *
      * @param tunnel The {@link IpSecManager#IpSecTunnelInterface} that will use the supplied
      *        transform.
      * @param direction the direction, {@link DIRECTION_OUT} or {@link #DIRECTION_IN} in which
diff --git a/service-t/src/com/android/server/IpSecService.java b/service-t/src/com/android/server/IpSecService.java
index 4bc40ea..16b9f1e 100644
--- a/service-t/src/com/android/server/IpSecService.java
+++ b/service-t/src/com/android/server/IpSecService.java
@@ -1452,6 +1452,11 @@
         final ConnectivityManager connectivityManager =
                 mContext.getSystemService(ConnectivityManager.class);
         final LinkProperties lp = connectivityManager.getLinkProperties(underlyingNetwork);
+        if (lp == null) {
+            throw new IllegalArgumentException(
+                    "LinkProperties is null. The underlyingNetwork may not be functional");
+        }
+
         if (tunnelInterfaceInfo.getInterfaceName().equals(lp.getInterfaceName())) {
             throw new IllegalArgumentException(
                     "Underlying network cannot be the network being exposed by this tunnel");
diff --git a/tests/unit/java/com/android/server/IpSecServiceParameterizedTest.java b/tests/unit/java/com/android/server/IpSecServiceParameterizedTest.java
index 45f3d3c..061dc87 100644
--- a/tests/unit/java/com/android/server/IpSecServiceParameterizedTest.java
+++ b/tests/unit/java/com/android/server/IpSecServiceParameterizedTest.java
@@ -783,6 +783,23 @@
     }
 
     @Test
+    public void testSetNetworkForTunnelInterfaceFailsForNullLp() throws Exception {
+        final IpSecTunnelInterfaceResponse createTunnelResp =
+                createAndValidateTunnel(mSourceAddr, mDestinationAddr, BLESSED_PACKAGE);
+        final Network newFakeNetwork = new Network(1000);
+        final int tunnelIfaceResourceId = createTunnelResp.resourceId;
+
+        try {
+            mIpSecService.setNetworkForTunnelInterface(
+                    tunnelIfaceResourceId, newFakeNetwork, BLESSED_PACKAGE);
+            fail(
+                    "Expected an IllegalArgumentException for underlying network with null"
+                            + " LinkProperties");
+        } catch (IllegalArgumentException expected) {
+        }
+    }
+
+    @Test
     public void testSetNetworkForTunnelInterfaceFailsForInvalidResourceId() throws Exception {
         final IpSecTunnelInterfaceResponse createTunnelResp =
                 createAndValidateTunnel(mSourceAddr, mDestinationAddr, BLESSED_PACKAGE);