add egress diagnostic util (#54)

Author: pgalbraith

src/main/java/test/EgressDiagnostics.java

@@ -0,0 +1,34 @@
+package test;
+
+import java.net.*;
+
+public class EgressDiagnostics {
+    public static void main(String[] args) throws SocketException {
+        System.out.println(System.getProperties());
+        tryRemote(new InetSocketAddress("a.root-servers.net", 0));
+        tryRemote(new InetSocketAddress("a.root-servers.net", 53));
+        tryRemote(new InetSocketAddress("1.1.1.1", 0));
+        tryRemote(new InetSocketAddress("1::1", 0));
+    }
+
+    public static void tryRemote(InetSocketAddress remote) {
+        DatagramSocket socket = null;
+        try {
+            System.out.println("\nremote: " + remote);
+            socket = new DatagramSocket();
+            socket.connect(remote);
+            InetAddress local = socket.getLocalAddress();
+            System.out.println("local: " + local);
+            NetworkInterface ni = NetworkInterface.getByInetAddress(local);
+            System.out.println("interface: " + ni);
+            System.out.println("hardware: " + ni.getHardwareAddress());
+        } catch (Throwable t) {
+            System.out.println(t);
+            t.printStackTrace();
+        } finally {
+            if (socket != null) {
+                socket.close();
+            }
+        }
+    }
+}