diff --git a/tests/cts/net/src/android/net/cts/ListeningPortsTest.java b/tests/cts/net/src/android/net/cts/ListeningPortsTest.java
new file mode 100644
index 0000000..ff6b4e9
--- /dev/null
+++ b/tests/cts/net/src/android/net/cts/ListeningPortsTest.java
@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.cts;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Scanner;
+import java.util.regex.Pattern;
+
+import junit.framework.TestCase;
+
+public class ListeningPortsTest extends TestCase {
+
+    /** Address patterns used to check whether we're checking the right column in /proc/net. */
+    private static final List<String> ADDRESS_PATTERNS = new ArrayList<String>(2);
+
+    static {
+        ADDRESS_PATTERNS.add("[0-9A-F]{8}:[0-9A-F]{4}");
+        ADDRESS_PATTERNS.add("[0-9A-F]{32}:[0-9A-F]{4}");
+    }
+
+    /** Ports that are allowed to be listening on the emulator. */
+    private static final List<String> EXCEPTION_PATTERNS = new ArrayList<String>(6);
+
+    static {
+        // IPv4 exceptions
+        EXCEPTION_PATTERNS.add("00000000:15B3"); // 0.0.0.0:5555   - emulator port
+        EXCEPTION_PATTERNS.add("0F02000A:15B3"); // 10.0.2.15:5555 - net forwarding for emulator
+        EXCEPTION_PATTERNS.add("[0-9A-F]{6}7F:[0-9A-F]{4}"); // IPv4 Loopback
+
+        // IPv6 exceptions
+        EXCEPTION_PATTERNS.add("[0]{31}1:[0-9A-F]{4}"); // IPv6 Loopback
+        EXCEPTION_PATTERNS.add("[0]{16}[0]{4}[0]{4}[0-9A-F]{6}7F:[0-9A-F]{4}"); // IPv4-6 Conversion
+        EXCEPTION_PATTERNS.add("[0]{16}[F]{4}[0]{4}[0-9A-F]{6}7F:[0-9A-F]{4}"); // IPv4-6 Conversion
+    }
+
+    public static void testNoListeningPorts() {
+        final boolean isTcp = true;
+        assertNoListeningPorts("/proc/net/tcp", isTcp);
+        assertNoListeningPorts("/proc/net/tcp6", isTcp);
+        assertNoListeningPorts("/proc/net/udp", !isTcp);
+        assertNoListeningPorts("/proc/net/udp6", !isTcp);
+    }
+
+    private static void assertNoListeningPorts(String procFilePath, boolean isTcp) {
+
+        /*
+         * Sample output of "cat /proc/net/tcp" on emulator:
+         *
+         * sl  local_address rem_address   st tx_queue rx_queue tr tm->when retrnsmt   uid  ...
+         * 0: 0100007F:13AD 00000000:0000 0A 00000000:00000000 00:00000000 00000000     0   ...
+         * 1: 00000000:15B3 00000000:0000 0A 00000000:00000000 00:00000000 00000000     0   ...
+         * 2: 0F02000A:15B3 0202000A:CE8A 01 00000000:00000000 00:00000000 00000000     0   ...
+         *
+         */
+
+        File procFile = new File(procFilePath);
+        Scanner scanner = null;
+        try {
+            scanner = new Scanner(procFile);
+            while (scanner.hasNextLine()) {
+                String line = scanner.nextLine().trim();
+
+                // Skip column headers
+                if (line.startsWith("sl")) {
+                    continue;
+                }
+
+                String[] fields = line.split("\\s+");
+                final int expectedNumColumns = 12;
+                assertTrue(procFilePath + " should have at least " + expectedNumColumns
+                        + " columns of output " + fields, fields.length >= expectedNumColumns);
+
+                String localAddress = fields[1];
+                String state = fields[3];
+
+                assertTrue(procFilePath + " should have an IP address in the second column",
+                        isAddress(localAddress));
+
+                if (!isException(localAddress) && isPortListening(state, isTcp)) {
+                    fail("Found port listening on " + localAddress + " in " + procFilePath);
+                }
+            }
+        } catch (FileNotFoundException notFound) {
+            fail("Could not open file " + procFilePath + " to check for listening ports.");
+        } finally {
+            if (scanner != null) {
+                scanner.close();
+            }
+        }
+    }
+
+    private static boolean isAddress(String localAddress) {
+        return isPatternMatch(ADDRESS_PATTERNS, localAddress);
+    }
+
+    private static boolean isException(String localAddress) {
+        return isPatternMatch(EXCEPTION_PATTERNS, localAddress);
+    }
+
+    private static boolean isPatternMatch(List<String> patterns, String input) {
+        for (String pattern : patterns) {
+            if (Pattern.matches(pattern, input)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private static boolean isPortListening(String state, boolean isTcp) {
+        // 0A = TCP_LISTEN from include/net/tcp_states.h
+        String listeningState = isTcp ? "0A" : "07";
+        return listeningState.equals(state);
+    }
+}