On Fri, 19 Nov 2004 17:13:37 +0000, Tony Finch <dot@???> wrote:
>On Fri, 19 Nov 2004, Marc Haber wrote:
>> Neither RFC states that Sender: should be generated automatically.
>
>However long-standing practice in Unix MTAs does say that it should.
If that long-standing practice is older than ten years, it should be
revised since the normal usage of Unixoid systems in daily life has
changed. A lot.
>> However, on today's systems is it neither guaranteed that UHacct has a
>> mailbox on h.example.com, nor is it guaranteed that h.example.com is
>> even reachable for SMTP from the outside at all. Hence, the automatic
>> generation of Sender: and envelope sender according to the local
>> account at the local host is bound to generate bad addresses on the
>> majority of systems out there, most probably the ones taken care of by
>> inexperienced people.
>
>That's incompetence on the part of the machine's administrator, setting
>the wrong qualify_domain. If you think this is likely amongst your user
>base you should alter your friendly Exim configuration script to encourage
>them to do the right thing.
It is likely amongst the user base of the majority of systems in use
nowadays that the owner neither has a static FQDN nor a static IP
address. And you don't want to have e-mails going out with
"debian_user@???" since that FQDN might belong
to somebody else in two minutes.
Additionally, if secretary@??? types an e-mail for
boss@??? and sends it out - correctly - with From:
boss@??? and Sender: secretary@???, it
is _not_ a good thing to overwrite the correct Sender with some
arbitrary value, destroying one of the useful applications of Sender:.
>> For tracing purposes, the account name and originating host can be
>> obtained from the Received:-Headers, or an optional
>> X-Authenticated-Sender which might be added for that purpose.
>> Unfortunately, exim can add the UHacct@??? either as Sender:
>> header or not at all. Maybe it would be a good idea to make the name
>> of the header added with the real account information configurable,
>> enabling sites to set some header like X-Authenticated-Sender to the
>> real account data if they wish to.
>
>You can add an appropriate header using Exim's existing facilities.
Where can I obtain exactly the same data that exim uses to generate
the Sender:
> If you
>are adding a special header then it isn't appropriate to give it the
>special semantics of Sender: which allow it to be omitted when it is the
>same as From:.
It is. If the From: has the right value for the authenticated sender
(which is almost never the case in today's use),
X-Authenticated-Sender or whatever it is named can be omitted as well.
Greetings
Marc
--
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Marc Haber | " Questions are the | Mailadresse im Header
Mannheim, Germany | Beginning of Wisdom " | http://www.zugschlus.de/
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