Re: [EXIM] [Followup] Explanation please: <<< 552 Header li…

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Author: Philip Hazel
Date:  
To: Chris Thompson
CC: exim-users
Subject: Re: [EXIM] [Followup] Explanation please: <<< 552 Header line is ridiculously overlong
On Mon, 31 May 1999, Chris Thompson wrote:

> So perhaps that makes it an FAQ...


Noted.

> In particular, it seems anomalous
> that Exim will reject
>
>   To: Alpha <aaaaaaaaaaaaaaaaaaaaaaaa@???>,
>       Bravo <bbbbbbbbbbbbbbbbbbbbbbbb@???>,
>       Charlie <cccccccccccccccccccccc@???>,
>       ...

>
> if it goes on too long, but not the same amount of data presented as
>
> To: Alpha <aaaaaaaaaaaaaaaaaaaaaaaa@???>
> To: Bravo <bbbbbbbbbbbbbbbbbbbbbbbb@???>
> To: Charlie <cccccccccccccccccccccc@???>
> ...


It does also limit the total *number* of headers (default 500), but of
course this might indeed not bite.

> It seems to me that it would make more sense to protect what is really
> at issue, by imposing a limit (alterable by configuaration file) on the
> *total* size of the headers, rather than the size of any one of them.


These limits date from the very early days of Exim and are some of the
first code I actually wrote. With hindsight, I think you are right, and
have made a note to consider making that change.

Incidentally, the revision of RFC 822 (still not quite published) makes
it clear that there should only be *one* "To:" header in a message, so
your second example above is strictly illegal, though I suspect few MTAs
would complain.

-- 
Philip Hazel            University of Cambridge Computing Service,
ph10@???      Cambridge, England. Phone: +44 1223 334714.



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