--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.dns.client/share/classes/jdk/dns/client/internal/PortConfig.java	Thu Oct 31 16:16:21 2019 +0000
@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.dns.client.internal;
+
+final class PortConfig {
+    /**
+     * Determines the ephemeral port range in use on this system.
+     * If this cannot be determined, then the default settings
+     * of the OS are returned.
+     */
+    private static int defaultUpper, defaultLower;
+    private static final int upper, lower;
+
+    private PortConfig() {
+    }
+
+    static {
+        String os = System.getProperty("os.name");
+        if (os.startsWith("Linux")) {
+            defaultLower = 32768;
+            defaultUpper = 61000;
+        } else if (os.startsWith("SunOS")) {
+            defaultLower = 32768;
+            defaultUpper = 65535;
+        } else if (os.contains("OS X")) {
+            defaultLower = 49152;
+            defaultUpper = 65535;
+        } else if (os.startsWith("AIX")) {
+            // The ephemeral port is OS version dependent on AIX:
+            // http://publib.boulder.ibm.com/infocenter/aix/v7r1/topic/com.ibm.aix.rsct315.admin/bl503_ephport.htm
+            // However, on AIX 5.3 / 6.1 / 7.1 we always see the
+            // settings below by using:
+            // /usr/sbin/no -a | fgrep ephemeral
+            defaultLower = 32768;
+            defaultUpper = 65535;
+        } else {
+            throw new InternalError(
+                    "sun.net.PortConfig: unknown OS");
+        }
+
+        lower = defaultLower;
+        upper = defaultUpper;
+    }
+
+    public static int getLower() {
+        return lower;
+    }
+
+    public static int getUpper() {
+        return upper;
+    }
+}