Re: [Shutup] [ietf-smtp] Proposed Charter for the "SMTP Headers Unhealthy To User Privacy" WG (fwd)

Hector Santos <> Tue, 01 December 2015 23:37 UTC

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Date: Tue, 01 Dec 2015 18:37:28 -0500
From: Hector Santos <>
Organization: Santronics Software, Inc.
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To: Christian Huitema <>, 'Martijn Grooten' <>,
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Subject: Re: [Shutup] [ietf-smtp] Proposed Charter for the "SMTP Headers Unhealthy To User Privacy" WG (fwd)
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On 12/1/2015 2:50 PM, Christian Huitema wrote:
> I am also concerned with automated mass surveillance, including traffic
> analysis. The basic traffic analysis produces "5-tupple" logs. Since a lot
> of the Internet usage is now mobile, there is no direct mapping between IP
> addresses and user identities. To move from traffic analysis to
> surveillance, the analyzers need to restore that mapping. There are multiple
> ways to do that, as explained in RFC 7624, and email headers are one of
> them.
> Clearly, there are also other sources of correlation between IP address and
> identity. Various IETF working groups are busy closing these other sources
> as well: MAC Address randomization to suppress direct mapping of identities
> to roaming devices; DHCP anonymity profile to remove the leakage of metadata
> in DNS packets; or, HTTPS to prevent observation of HTTP cookies. To break
> the correlation between IP address and identity, we need to also close the
> leakage in the SMTP traces.
> Everybody understands that there is a tension there between privacy and
> fighting spam. I get the use case of the virus-infected home PC that
> originates spam through the permissive SMTP relay of some local ISP. But
> then many mail providers feel the need to provide privacy to their users,
> which drives them to deploy their own formatting of the "received" field. We
> do have a tension there, and that tension is precisely why we want to study
> the alternatives and come up with a proposed recommendation. Hence the WG
> charter.

I'm all for "generalized" product enhancement features.

So you are proposing for SMTP developers to consider adding SMTP 
Receiver options such as:

   [X] Add "Received:" Header
       [_] Mask User IP address

Should this be at the USER or SYSTEM level? Both?   Effectively, we 
would be changing RFC5321 from a MUST to a SHOULD|MAY where a required 
protocol feature becomes optional.