Re: [ietf-smtp] [Emailcore] Proposed ESMTP keyword RCPTLIMIT
Ned Freed <ned.freed@mrochek.com> Tue, 20 April 2021 17:39 UTC
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Cc: Ned Freed <ned.freed@mrochek.com>, ietf-smtp@ietf.org
Message-id: <01RY3AB1YBI80085YQ@mauve.mrochek.com>
Date: Tue, 20 Apr 2021 10:31:02 -0700
From: Ned Freed <ned.freed@mrochek.com>
In-reply-to: "Your message dated Tue, 20 Apr 2021 16:53:45 +0100" <vQ24SenJkvfgFAH3@highwayman.com>
References: <cone.1615844513.220592.51342.1004@monster.email-scan.com> <20210315234648.563C0708B340@ary.qy> <CAO=DXp-+fJwsNegzu3zgwDLtCcSF104AUF=i+_GMgSYVBAKjWg@mail.gmail.com> <01RY24IJ225Q0085YQ@mauve.mrochek.com> <CAO=DXp-VSxeTsWZFAms7WX-jonkSiyGgKV5T_17VGhq6bcsMdg@mail.gmail.com> <cone.1618877363.380527.55051.1004@monster.email-scan.com> <F8AC11B4-1C30-4DE6-AE70-F91994EE7539@wordtothewise.com> <Dx8j6QnjLufgFAwC@highwayman.com> <01RY347LHNBA0085YQ@mauve.mrochek.com> <vQ24SenJkvfgFAH3@highwayman.com>
To: Richard Clayton <richard@highwayman.com>
Archived-At: <https://mailarchive.ietf.org/arch/msg/ietf-smtp/v6ckA4y2qiqVnJ3IPRTFAFec-rM>
Subject: Re: [ietf-smtp] [Emailcore] Proposed ESMTP keyword RCPTLIMIT
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> In message <01RY347LHNBA0085YQ@mauve.mrochek.com>, Ned Freed > <ned.freed@mrochek.com> writes > >> as I observed before -- don't expect much more than a generic statement > >> (which comes down to "sending N good emails is the most you can expect > >> to be able to manage") from such systems. Anything which revealed the > >> current view ("actually, you've pretty much exhausted our patience") > >> just is not going to happen (IMO) > > > >I don't really understand the concern here, > Some bad senders start by sending good email and then, once their > reputation is established, send bad email. It is generally thought to be > unwise to give any clues whatsoever as to how well this process might be > going... (to what extent the machine learning system has been fooled) > >and more importantly, how to address > >it. > It is inherent that you cannot -- so mailbox providers who operate in > the space where this is a significant issue are not going to provide any > fine-grained data whatsoever -- just generic values. That's not what I meant by "address". It's important that standards discuss all known security issues; and this definitely qualifies. As such, I'm going to add this text to the Security Considerations: Use of the Limits extension to provide client-specific information - as opposed to general server limits - unavoidably provides senders with feedback about their reputation. Malicious senders can exploit this in various ways, e.g., start by sending good email and then, once their reputation is established, sending bad email. > I take Laura's point that good senders can deduce the upper limits -- > and hence providing data about those upper limits at the start of the > session has a small amount of value (if only in ensuring that sessions > close smoothly and fewer exception logging event are generated) Speaking as someone who works on software used for bulk sending, the the value isn't small, especially when you take the ability to shape subsequent traffic into account. Ned
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Ned Freed
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Dave Crocker
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Viktor Dukhovni
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Ned Freed
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Dave Crocker
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Ned Freed
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Viktor Dukhovni
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… John Levine
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Ned Freed
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Ned Freed
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… John C Klensin
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Ned Freed
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Rolf E. Sonneveld
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Sam Varshavchik
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Ned Freed
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… John Levine
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… John C Klensin
- Re: [ietf-smtp] parsing SMTP replies (was: Propos… Claus Assmann
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Ned Freed
- Re: [ietf-smtp] parsing SMTP replies (was: Propos… Alessandro Vesely
- Re: [ietf-smtp] parsing SMTP replies (was: Propos… Ned Freed
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Jeremy Harris
- Re: [ietf-smtp] parsing SMTP replies (was: Propos… John C Klensin
- Re: [ietf-smtp] parsing SMTP replies (was: Propos… Sam Varshavchik
- Re: [ietf-smtp] parsing SMTP replies (was: Propos… Keith Moore
- Re: [ietf-smtp] parsing SMTP replies (was: Propos… Viktor Dukhovni
- Re: [ietf-smtp] parsing SMTP replies (was: Propos… Valdis Kl ē tnieks
- Re: [ietf-smtp] parsing SMTP replies (was: Propos… Valdis Kl ē tnieks
- Re: [ietf-smtp] parsing SMTP replies (was: Propos… John C Klensin
- Re: [ietf-smtp] parsing SMTP replies (was: Propos… Alessandro Vesely
- Re: [ietf-smtp] parsing SMTP replies Keith Moore
- Re: [ietf-smtp] parsing SMTP replies (was: Propos… John C Klensin
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… John C Klensin
- Re: [ietf-smtp] parsing SMTP replies Michael Peddemors
- Re: [ietf-smtp] parsing SMTP replies Ned Freed
- Re: [ietf-smtp] parsing SMTP replies Viktor Dukhovni
- Re: [ietf-smtp] parsing SMTP replies Michael Peddemors
- Re: [ietf-smtp] parsing SMTP replies Jeremy Harris
- Re: [ietf-smtp] parsing SMTP replies Laura Atkins
- Re: [ietf-smtp] parsing SMTP replies George Schlossnagle
- Re: [ietf-smtp] parsing SMTP replies Ned Freed
- Re: [ietf-smtp] parsing SMTP replies (was: Propos… Ned Freed
- Re: [ietf-smtp] parsing SMTP replies (was: Propos… Ned Freed
- Re: [ietf-smtp] parsing SMTP replies Richard Clayton
- Re: [ietf-smtp] parsing SMTP replies Hector Santos
- Re: [ietf-smtp] parsing SMTP replies Laura Atkins
- Re: [ietf-smtp] parsing SMTP replies Ned Freed
- Re: [ietf-smtp] parsing SMTP replies John C Klensin
- Re: [ietf-smtp] parsing SMTP replies Hector Santos
- Re: [ietf-smtp] parsing SMTP replies Hector Santos
- Re: [ietf-smtp] parsing SMTP replies Laura Atkins
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… John Levine
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Jeremy Harris
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Ned Freed
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… John Levine
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… George Schlossnagle
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Hector Santos
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Mike Hillyer
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Ned Freed
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Ned Freed
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… John R Levine
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Michael Peddemors
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Jeremy Harris
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… George Schlossnagle
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Ned Freed
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Sam Varshavchik
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Laura Atkins
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Arnt Gulbrandsen
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Mike Hillyer
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Dave Crocker
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Richard Clayton
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Laura Atkins
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Ned Freed
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Ned Freed
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… John R Levine
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Richard Clayton
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Ned Freed
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Tony Finch
- Re: [ietf-smtp] [Emailcore] Proposed ESMTP keywor… Viktor Dukhovni