IETF Logo Mail Archive

Re: [tcpm] 793bis IESG comment on NAT64 and MSS

"touch@strayalpha.com" <touch@strayalpha.com> Wed, 01 December 2021 04:47 UTC

Return-Path: <touch@strayalpha.com>
X-Original-To: tcpm@ietfa.amsl.com
Delivered-To: tcpm@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id EA0343A0A80 for <tcpm@ietfa.amsl.com>; Tue, 30 Nov 2021 20:47:30 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.318
X-Spam-Level:
X-Spam-Status: No, score=-1.318 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, HTML_MESSAGE=0.001, SPF_HELO_NONE=0.001, SPF_NEUTRAL=0.779, URIBL_BLOCKED=0.001] autolearn=no autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=strayalpha.com
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id R_nBjG2KUExP for <tcpm@ietfa.amsl.com>; Tue, 30 Nov 2021 20:47:26 -0800 (PST)
Received: from server217-1.web-hosting.com (server217-1.web-hosting.com [198.54.114.226]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 53A883A0A7E for <tcpm@ietf.org>; Tue, 30 Nov 2021 20:47:26 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=strayalpha.com; s=default; h=To:References:Message-Id:Cc:Date:In-Reply-To: From:Subject:Mime-Version:Content-Type:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=i0G5L6ZbWzptdPDuK3cl0gZWZF0+UtXPpnSNpcMp1V0=; b=13tG2afuXEFbsZ/epYLTYY0s2T la0JNsrfRvtMuZ8ZAnNuqbhs1qGifH7el4f+NiZ2uXc+u16iK3VAOiQqSxgNLCJ1WZ7p7woJFXDFI mIYM5USX3xUKyqB5YeX02BiwXPNzpJEBPaDnR4vKb8gACeoNf9Q3JVDxYMa6HHKd69mtov+7GZQFx eROXl0LD5XehmPppeSN39U8fkWqEi3U2BQ1rfMA/3OCEY0759tCrmCOT17M4ZWjynKSmXBQCleeMz xuBziMFnp8YA2FvEs7oRATjfcDb9FaWUAP4fXU8ImDevGabNfuLpROlH2Zggv00HmAkfW+o3TPxfW bxHBRJAw==;
Received: from cpe-172-114-237-88.socal.res.rr.com ([172.114.237.88]:59720 helo=smtpclient.apple) by server217.web-hosting.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from <touch@strayalpha.com>) id 1msHWa-0037OW-ES; Tue, 30 Nov 2021 23:47:25 -0500
Content-Type: multipart/alternative; boundary="Apple-Mail=_EB378ED2-9480-4447-ADC2-31EEE1A4C201"
Mime-Version: 1.0 (Mac OS X Mail 15.0 \(3693.20.0.1.32\))
From: "touch@strayalpha.com" <touch@strayalpha.com>
In-Reply-To: <78967f83-12a1-7f0c-4919-833e5120b49b@mti-systems.com>
Date: Tue, 30 Nov 2021 20:47:17 -0800
Cc: tcpm IETF list <tcpm@ietf.org>
Message-Id: <9AAF79C1-9F0B-4CF0-9A77-13D97C0F8308@strayalpha.com>
References: <78967f83-12a1-7f0c-4919-833e5120b49b@mti-systems.com>
To: Wes Eddy <wes@mti-systems.com>
X-Mailer: Apple Mail (2.3693.20.0.1.32)
X-OutGoing-Spam-Status: No, score=-1.0
X-AntiAbuse: This header was added to track abuse, please include it with any abuse report
X-AntiAbuse: Primary Hostname - server217.web-hosting.com
X-AntiAbuse: Original Domain - ietf.org
X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12]
X-AntiAbuse: Sender Address Domain - strayalpha.com
X-Get-Message-Sender-Via: server217.web-hosting.com: authenticated_id: touch@strayalpha.com
X-Authenticated-Sender: server217.web-hosting.com: touch@strayalpha.com
X-Source:
X-Source-Args:
X-Source-Dir:
X-From-Rewrite: unmodified, already matched
Archived-At: <https://mailarchive.ietf.org/arch/msg/tcpm/6yS7vQU4SaopXqJx9wZkcmGXK-4>
Subject: Re: [tcpm] 793bis IESG comment on NAT64 and MSS
X-BeenThere: tcpm@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: TCP Maintenance and Minor Extensions Working Group <tcpm.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/tcpm>, <mailto:tcpm-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/tcpm/>
List-Post: <mailto:tcpm@ietf.org>
List-Help: <mailto:tcpm-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/tcpm>, <mailto:tcpm-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 01 Dec 2021 04:47:32 -0000

Hi, Wes,

IMO, the text is clear and sufficient. There are many reasons why the MSS should be sent or why it could be asymmetric (e.g., asymmetric routes with different tunnels); it doesn’t make sense to try to list them all or highlight any.

I agree this probably should have been dealt with in RFC6146, but adding this to TCPbis is not an appropriate fix for that omission.

Joe

—
Joe Touch, temporal epistemologist
www.strayalpha.com

> On Nov 30, 2021, at 6:35 PM, Wesley Eddy <wes@mti-systems.com> wrote:
> 
> Here is another interesting point in the IESG ballots from Erik Kline that it would be good to get list feedback on:
> 
> [S3.7.1, comment]
> 
> * In networks where NAT64 is employed, the default MSS assumed by a sender
>   will differ from the default assumed by a receiver, since the address
>   families sent and received will be different.
> 
>   This may bolster the case for MAY-3 being a SHOULD (or even a MUST ;-) but,
>   more to the point, may be a caveat to note w.r.t. SHLD-5.
> 
>   Alas, I could find no discussion of MSS option handling in RFC 6146,
>   so I wonder if that's something that we missed...
> For reference, MAY-3 and SHLD-5 come from: 
> 
>    TCP implementations SHOULD send an MSS option in every SYN segment
>    when its receive MSS differs from the default 536 for IPv4 or 1220
>    for IPv6 (SHLD-5), and MAY send it always (MAY-3).
> 
> It's not entirely clear to me whether there is something within the 793bis scope to do about this, or if it should be saved as a possible bit of "future work" for maintenance regarding NAT64 and transport notions of MSS (which should impact more than just TCP).
> 
> 
> 
> _______________________________________________
> tcpm mailing list
> tcpm@ietf.org
> https://www.ietf.org/mailman/listinfo/tcpm

v2.23.0 | Report a Bug | By Email