On Tue, Sep 01, 2015 at 11:03:56PM +0000, admin@??? wrote:
> https://bugs.exim.org/show_bug.cgi?id=1684
>
> --- Comment #2 from Heiko Schlittermann <hs@???> ---
> Exim should not accept messages with such oversized lines. This can be
> accomplished by an ACL entry in the DATA ACL.
The limitation in question is specific to SMTP, and not all mail
is delivered via SMTP. Some might be purely local. Requiring an
ACL for this is not very elegant IMHO.
> Once the message is accepted, Exim should do it's best to transmit it.
> I'm not sure if reformatting the oversized headers is a good solution. Exim
> should not touch any content of the message ever.
Yes, but garbage in, best effort out. FWIW, Postfix folds such
headers (that should have been folded upstream by the MUA) by
inserting <SPACE><CRLF> once the limit is reached. Even better
code would try to find a semantically appropriate context for the
fold (e.g. after a "," separating multiple message-ids in a References
header). Semantically sound folding is not implemented in Postfix,
no noticeable complaints, though some long References headers
generated by some Exchange or Outlook versions do become a bit of
a mess given enough round-trips.
Blocking such mail is likely too drastic.
--
Viktor.
