Re: [TLS] ECH-10 interop test server

Rob Sayre <> Fri, 28 May 2021 18:36 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id B89253A316B for <>; Fri, 28 May 2021 11:36:08 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -2.096
X-Spam-Status: No, score=-2.096 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: (amavisd-new); dkim=pass (2048-bit key)
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id LhM3o_4kpzLx for <>; Fri, 28 May 2021 11:36:04 -0700 (PDT)
Received: from ( [IPv6:2607:f8b0:4864:20::12e]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 1E1AD3A3160 for <>; Fri, 28 May 2021 11:36:04 -0700 (PDT)
Received: by with SMTP id u3so4130593ilv.8 for <>; Fri, 28 May 2021 11:36:03 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=gkfb106mU7Z/UJmOm6QdU6kev8h35A+R5iSfrX6WX4s=; b=Yeg5MXq+UZNcfnJDllki7yjTQgBOh37j6S3UFlJkrBn/qtbJFLhlQIrlkMsfD5rjfh 1lKH1x3NQankG/W7tXYY8bP5J8IS86OoWjO+Wx83lzVeQK12Hnl97bk8TZFBLXbq0guF XidQhcXM7jtR9x+UyrDeBMgn9NmKImqmaMmw601WB2AbWDO6bB+hpFJ6C7pP/H2VFs9i K4A7bNbW/MMzFnp9jT/BlwLOePQPs7gnIS2oUYK7F98nNOhe1ZDF+ikjdwKeL/y/7H3D b6qTBp5sCWrdr8FgtwKluJvUw763Dwdb5c4ZtmylfDB6YFvOj9qxGNsVKkQ3yO7Stb7P QlNw==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=gkfb106mU7Z/UJmOm6QdU6kev8h35A+R5iSfrX6WX4s=; b=eirLZXPdxsI2eSTO4Sk5Oe7DD+LSH5QwD2dFsbl65gk6s44uAO/eMFTp8oQat5Rymc fwf3LSbXKxDtWE0s1AMxHTiwi6LK7KifRIL8xRodFCukleUpihp932RB2k8HwahZTsO9 ygoKyWAiJYpTj3fIjcFmmXB5Rgt+LrpR4eKf2gjgNsFnVidKdDvNSRHZ70HjDd4Rufb/ BCPQprfCGfheGOzIA3/Nn4KelaYoh0rIaayXu9od0D8VJXYg3w/mZ5LRr2yd7iJ/N/Tl V0q3xuu6IEc3lAU/l82Q0RXBqqoQpmZHuZOF5RBIoFu2exTq35cvGiwXOrQZzwKOnWVw ca9Q==
X-Gm-Message-State: AOAM5301vBbMiOVwFx6yqhwCfxpiR1j7jG76TJeZLPuvfmjJoZXE0VH7 9ZDrLg+lkS4EY9bLVe1/kPFlxSj69s/4xy+QvnE=
X-Google-Smtp-Source: ABdhPJyp4S4EFoWMeY8eXeE6C4knhrIAPmyj0EQx2tl8wyp4IqTEI+l7yDFm8Bpa8u5irfMaN1rJ+VX8bJ2OHGUmFvg=
X-Received: by 2002:a05:6e02:e42:: with SMTP id l2mr8044891ilk.189.1622226959690; Fri, 28 May 2021 11:35:59 -0700 (PDT)
MIME-Version: 1.0
References: <>
In-Reply-To: <>
From: Rob Sayre <>
Date: Fri, 28 May 2021 11:35:48 -0700
Message-ID: <>
To: Christopher Patton <>
Cc: "<>" <>
Content-Type: multipart/alternative; boundary="000000000000ad704805c36825a0"
Archived-At: <>
Subject: Re: [TLS] ECH-10 interop test server
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "This is the mailing list for the Transport Layer Security working group of the IETF." <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Fri, 28 May 2021 18:36:09 -0000

On Mon, Apr 5, 2021 at 10:02 AM Christopher Patton <cpatton=> 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 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.