diff --git a/Lib/http/server.py b/Lib/http/server.py
--- a/Lib/http/server.py
+++ b/Lib/http/server.py
@@ -355,7 +355,7 @@
 
         """
         self.send_response_only(100)
-        self.flush_headers()
+        self.end_headers()
         return True
 
     def handle_one_request(self):