diff --git a/Lib/socketserver.py b/Lib/socketserver.py
index a2f0f39..5e909c8 100644
--- a/Lib/socketserver.py
+++ b/Lib/socketserver.py
@@ -199,6 +199,7 @@ class BaseServer:
         self.server_address = server_address
         self.RequestHandlerClass = RequestHandlerClass
         self.__is_shut_down = threading.Event()
+        self.__is_shut_down.set()
         self.__shutdown_request = False
 
     def server_activate(self):
diff --git a/Lib/test/test_socketserver.py b/Lib/test/test_socketserver.py
index 08d79c0..36613db 100644
--- a/Lib/test/test_socketserver.py
+++ b/Lib/test/test_socketserver.py
@@ -273,6 +273,19 @@ class SocketServerTest(unittest.TestCase):
             t.join()
             s.server_close()
 
+    def test_shutdown_without_serve_forever(self):
+        # issue 12463: shutdown() without serve_forver() must not hang
+
+        class MyServer(socketserver.TCPServer):
+            pass
+
+        class MyHandler(socketserver.StreamRequestHandler):
+            pass
+
+        s = MyServer((HOST, 0), MyHandler)
+        s.shutdown()
+        s.server_close()
+
 
 def test_main():
     if imp.lock_held():