Re: To all who wish to unsubscribe

On 2017-11-20 21:03, Tom Lane wrote:
> "Joshua D. Drake" <jd(at)commandprompt(dot)com> writes:
>> On 11/20/2017 11:40 AM, Magnus Hagander wrote:
>> One thing I would note is that there is no longer a footer that
>> tells people what to do if they want to unsubscribe. Perhaps one
>> thing that could be done is a header (for a temporary time period)
>> that says:
>> The mailing list software of Postgresql.org has changed. Please see
>> this page on instructions on how to manage your subscription and
>> filters. And then after the temporary time period that becomes a
>> footer?
>
> Unfortunately, the removal of the footer is a feature not a bug. In
> order to be DKIM-compatible and thus help avoid becoming classified
> as spammers, we can't mangle message content anymore, just like we
> can't mangle the Subject: line.
I don't miss the footers, but see RFC 6376, "5.3.1. Body Length Limits".
Two fragments quoted are copied below:

> A body length count MAY be specified to limit the signature
> calculation to an initial prefix of the body text, measured in
> octets. If the body length count is not specified, the entire message
> body is signed.

> INFORMATIVE RATIONALE: This capability is provided because it is very
> common for mailing lists to add trailers to messages (e.g.,
> instructions on how to get off the list). Until those messages are
> also signed, the body length count is a useful tool for the Verifier
> since it can, as a matter of policy, accept messages having valid
> signatures with extraneous data.