#11227: use Host header in asyncore example.
diff --git a/Doc/library/asyncore.rst b/Doc/library/asyncore.rst
index eca4d1b..b6fe2bb 100644
--- a/Doc/library/asyncore.rst
+++ b/Doc/library/asyncore.rst
@@ -263,7 +263,8 @@
            asyncore.dispatcher.__init__(self)
            self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
            self.connect( (host, 80) )
-           self.buffer = bytes('GET %s HTTP/1.0\r\n\r\n' % path, 'ascii')
+           self.buffer = bytes('GET %s HTTP/1.0\r\nHost: %s\r\n\r\n' %
+                               (path, host), 'ascii')
 
        def handle_connect(self):
            pass