Subject: Re: [TLS] ECH-10 interop test server

From: Rob Sayre <[email-masked]>
Date: Fri, 28 May 2021 11:35:48 -0700

On Mon, Apr 5, 2021 at 10:02 AM Christopher Patton <cpatton=
[email-masked]> wrote:

> Hi list, just FYI that Cloudflare's test server is upgrading to
> draft-ietf-tls-esni-10 this morning. It should finish rolling out in a few
> hours. Note that we've dropped support for draft-ietf-tls-esni-09.
>
> The endpoint is https://crypto.cloudflare.com. You'll also find our ECH
> config in the HTTPS resource record.
>

I've gotten a Rustls client to interoperate with this server, but I had
some trouble triggering HRR, since Rustls always sends a key-exchange group
in TLS 1.3. I managed to hack up a ClientHello and handshake with no
initial key-exchange group, but perhaps it could be easier.

It might be nice to have this server reject secp384r1 and offer X25519 in
an HRR, or something like that.

thanks,
Rob