Re: [Exim] Adding a disclaimer to out going emails

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Author: Nigel Metheringham
Date:  
To: Marsh, Ian
CC: 'exim-users@exim.org'
Subject: Re: [Exim] Adding a disclaimer to out going emails
Ian.Marsh@??? said:
> The server that exim run on is a central hub with no local users,
> there are various lookups that determine if the email passing through
> is inbound or not. Anything going out is passed to a single router so
> I guess that something in there (or a custom transport used only by
> that router) would be the place to put it but I'm not sure exactly how
> to do it. Has anyone done this? Any suggestions would be welcome.


This keeps coming up (Philip - can something be added to the FAQ?)

The short answer is that it can be done in theory and the place to do
that would be in a transport filter.

My standard answer follows:-
Adding footers to mail in the MTA is wrong because:-
  1. It breaks digital signatures.  As these became legally binding 
     in the last few weeks thats particularly bad timing


2. It breaks MIME encoding

  3. It is illegal under German and Dutch law to change the body of
     a mail message in transit.  It might potentially be illegal in
     the UK under European law.


  4. Since the delivered message body was produced by the MTA (not the
     originator since you modified it), the MTA operator could 
     potentially be sued for any content.
     [Its interesting that adding a disclaimer of liability *could*
     be making you liable for the message :-) ]


  5. Some mail clients (old versions of MS outlook) crash if the message
     body of an incoming MIME message has been tampered with.


6. It is not the job of an MTA to modify content.


    Nigel.
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[ Nigel Metheringham                  Nigel.Metheringham@??? ]
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