Invalid HTTP2 preface handling?

Section 3.5 says:

   Clients and servers MUST treat an invalid connection preface as a
   connection error (Section 5.4.1
   frame (Section 6.8
MAY be omitted in this case, since an invalid
   preface indicates that the peer is not using HTTP/2.

I'm wondering what would be the problem if on an invalid preface, the
server check if it is actually a valid HTTP/1 request and if so, then to
proceed on that basis?     This would allow a server to converse a HTTP/1
client that is pointed at a HTTP/2 port - it could be application specific
if that conversation was an error message or just a normal HTTP/1

Is there some attack we would be enabling if we allowed such behaviour in
our server?  Anything else undesirable about doing this?


Greg Wilkins <>  @  Webtide - *an Intalio subsidiary* HTTP, SPDY, Websocket server and client that scales  advice and support for jetty and cometd.

Received on Tuesday, 10 February 2015 23:49:20 UTC