diff -r 1d72402c1c91 Lib/http/server.py
--- a/Lib/http/server.py	Tue Mar 15 13:33:28 2016 +1300
+++ b/Lib/http/server.py	Fri Mar 18 12:05:16 2016 +0800
@@ -137,7 +137,7 @@
     def server_bind(self):
         """Override server_bind to store the server name."""
         socketserver.TCPServer.server_bind(self)
-        host, port = self.socket.getsockname()[:2]
+        host, port = self.server_address[:2]
         self.server_name = socket.getfqdn(host)
         self.server_port = port
 
@@ -283,12 +283,9 @@
         words = requestline.split()
         if len(words) == 3:
             command, path, version = words
-            if version[:5] != 'HTTP/':
-                self.send_error(
-                    HTTPStatus.BAD_REQUEST,
-                    "Bad request version (%r)" % version)
-                return False
             try:
+                if version[:5] != 'HTTP/':
+                    raise ValueError
                 base_version_number = version.split('/', 1)[1]
                 version_number = base_version_number.split(".")
                 # RFC 2145 section 3.1 says there can be only one "." and
@@ -310,7 +307,7 @@
             if version_number >= (2, 0):
                 self.send_error(
                     HTTPStatus.HTTP_VERSION_NOT_SUPPORTED,
-                    "Invalid HTTP Version (%s)" % base_version_number)
+                    "Invalid HTTP version (%s)" % base_version_number)
                 return False
         elif len(words) == 2:
             command, path = words
@@ -338,6 +335,12 @@
                 HTTPStatus.BAD_REQUEST,
                 "Line too long")
             return False
+        except http.client.HTTPException:
+            self.send_error(
+                HTTPStatus.BAD_REQUEST,
+                "Too many headers"
+            )
+            return False
 
         conntype = self.headers.get('Connection', "")
         if conntype.lower() == 'close':
@@ -475,17 +478,17 @@
 
     def send_response_only(self, code, message=None):
         """Send the response header only."""
-        if message is None:
-            if code in self.responses:
-                message = self.responses[code][0]
-            else:
-                message = ''
         if self.request_version != 'HTTP/0.9':
+            if message is None:
+                if code in self.responses:
+                    message = self.responses[code][0]
+                else:
+                    message = ''
             if not hasattr(self, '_headers_buffer'):
                 self._headers_buffer = []
-            self._headers_buffer.append(("%s %d %s\r\n" %
-                    (self.protocol_version, code, message)).encode(
-                        'latin-1', 'strict'))
+            self._headers_buffer.append(
+                ("%s %d %s\r\n" % (self.protocol_version, code, message))
+                .encode('latin-1', 'strict'))
 
     def send_header(self, keyword, value):
         """Send a MIME header to the headers buffer."""
diff -r 1d72402c1c91 Lib/test/test_httpservers.py
--- a/Lib/test/test_httpservers.py	Tue Mar 15 13:33:28 2016 +1300
+++ b/Lib/test/test_httpservers.py	Fri Mar 18 12:05:16 2016 +0800
@@ -859,6 +859,14 @@
         self.assertFalse(self.handler.get_called)
         self.assertEqual(self.handler.requestline, 'GET / HTTP/1.1')
 
+    def test_too_many_headers(self):
+        headers = ['header%d: test\r\n' for i in range(101)]
+        result = self.send_typical_request(
+            b'GET / HTTP/1.1\r\n' + ''.join(headers).encode('utf-8') + b'\r\n')
+        self.assertEqual(result[0], b'HTTP/1.1 400 Too many headers\r\n')
+        self.assertFalse(self.handler.get_called)
+        self.assertEqual(self.handler.requestline, 'GET / HTTP/1.1')
+
     def test_close_connection(self):
         # handle_one_request() should be repeatedly called until
         # it sets close_connection