Re: [Exim] Re: bare linefeeds in SMTP

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Author: Kjetil Torgrim Homme
Date:  
To: exim-users
Subject: Re: [Exim] Re: bare linefeeds in SMTP
On Thu, 2003-12-18 at 04:34, Vineet Kumar wrote:
> * Kjetil Torgrim Homme (kjetilho@???) [031217 14:04]:
> > [...] let's "force" people to follow
> > the standards. the good guys generally do, it's the quick "let's write
> > a visual basic program to spam millions of people" who get it wrong.
>
> This doesn't work. Trying to "force" people to follow a standard by
> breaking the golden rule of interoperability generally results in nobody
> using your product, since it appears broken to real-world users.


being a University, we can afford to stick to standards. yes, this did
once mean that e-mail confirmations from a travel agents who had bought
a defective e-mail service didn't get through, but I hold that this is
the travel agent's problem. if thousands of our employees can't use
their service, that should be an incentive to get their system fixed.

> I'd be fine with exim having options to support this sort of strict
> compliance at the expense of interoperability, as long as the defaults
> are sane (liberal for the sake of interoperability).


the current handling of LF must be fixed. it's not pretty to receive
messages with no real headers, only the automatically generated ones.

> Perhaps this can be an extension of verify = header_syntax.


that sounds like a reasonable idea

> Maybe someone here can even figure out a way to do it with the existing acl
> infrastructure.


I doubt that is possible, the mangling of CRLF into LF seems to happen
before the ACLs have a chance to take a peek:

acl_check_data:
  deny    condition     = ${if match {$message_headers}{z\n} {yes}{no}}
  accept


this triggered when given a message with a header ending with z CRLF.

(ah -- the test was done with a pretty old version of Exim, 4.12)

--
Kjetil T.