Daniel Stenberg wrote:

>> Not sure I understand why the ALPN "fails" in libcurl (Win-10/MSVC,
>> OpenSSL/1.1.0). This "Application Layer Protocol Negotiation" works
>> fine in my Google Chrome:
>> Application Layer Protocol Negotiation Yes h2 spdy/3.1 http/1.1
>
> Really? Neither Firefox nor Chrome on my Linux box negotiate h2 on www.ssllabs.com for me!

Yes, my Chrome version is 50.0.2661.102m (the very latest).
If you look under chrome://net-internals/#http2, you should see:
  ALPN Protocols: h2,spdy/3.1,http/1.1
  NPN Protocols: h2,spdy/3.1,http/1.1

And capturing live events while at https://www.ssllabs.com/ssltest/viewMyClient.html
would show more details. Not sure if Chrome on Linux returns the same.

>> The page:
>> https://en.wikipedia.org/wiki/Application-Layer_Protocol_Negotiation
>>
>> says "It is used by HTTP/2". It doesn't says "HTTP/2" is required.
>
> That's correct. ALPN is just a TLS extension for negotiating which protocol to use "behind" TLS, so it could be used by
> just about any protocols. HTTP/2 is the posted child for it though and is the protocol (version) the extension was made
> for.

Thanks Daniel and Ray.

-- 
--gv
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