ok.
philip, your advice is excellent: it has allowed me to see what is going
on and compare two sets of results.
you can, if you so wish, see these two files and the diff, at:
http:hands.com/~lkcl/exim4_debug/
the diff (in the randomly named file 'f') highlights an example config
option that shows how to specify 'empty' (in the acl section covering
greylisting)
actually - it's _not_ comparing against 'empty', it's comparing against
a list of two items where the 2nd item is implicity ignored because
it's next to the end-of-line character, where the first item ends up
being the empty string. not quite the same thing, and a very odd
workaround, but close enough :)
[btw it's very very odd to have config files which don't use matched
characters to delimit parameters, but anyway...]
anyway - it answers one of my questions, but i don't believe that it
solves the issue.
ok. i think i know what's happening - or, more specifically, what
_isn't_ happening.
the combinations are as follows:
<>
<@localhost>
<fakeuser>
<fakeuser@>
if you try <@localhost>, then you get this:
MAIL FROM:<@localhost>
SMTP<< MAIL FROM:<@localhost>
LOG: smtp_syntax_error MAIN
SMTP syntax error in "MAIL FROM:<@localhost>" H=localhost [127.0.0.1] no local part
SMTP>> 501 <@localhost>: no local part
ok, so _that's_ ok - it says 'no local part' (which, btw is exactly how
<> should be treated, but i'll get on to that in a second...)
so, let's try the next one:
MAIL FROM:<fakeuser>
SMTP<< MAIL FROM:<fakeuser>
SMTP>> 501 <fakeuser>: sender address must contain a domain
501 <fakeuser>: sender address must contain a domain
LOG: smtp_syntax_error MAIN REJECT
unqualified sender rejected: <fakeuser> H=localhost [127.0.0.1]
ok, so _that_ isn't acceptable.
now, finally, let's try this:
MAIL FROM:<fakeuser@>
SMTP<< MAIL FROM:<fakeuser@>
LOG: smtp_syntax_error MAIN
SMTP syntax error in "MAIL FROM:<fakeuser@>" H=localhost [127.0.0.1] domain missing or malformed
SMTP>> 501 <fakeuser@>: domain missing or malformed
501 <fakeuser@>: domain missing or malformed
ok, so _that_ isn't accepted, _either_!
so, what's so special about <> that it has to be allowed and accepted by
exim4????
if you can't do <user> because you have to do <user@localhost>
if you can't do <@localhost> because it doesn't have a 'local part'
if you can't do <user@> because it doesn't have a 'domain'
then _what_ is so damn special about <> that it has to be accepted
and then has to be dealt with by configuration files?
at least there's a temporary fix without requiring a recompiled
exim4, and the bad thing is that the temporary fix needs to go into
absolutely _everyone's_ exim4 config files, and i mean absolutely
everyone.
_now_ can you appreciate why i believe this to be a bug in exim4, that
has nothing to do with configuration files??
if exim4 special-cases <@localhost> hard-coded handling without config
file intervention, if exim4 special-cases <fakeuser> hard-coded handling
without config file intervention, if exim4 special-cases <fakeuser@>
hard-coded handling without config file intervention, then why isn't it
special-case hard-coded rejecting <> as well???
in the mean-time, i am adding this, and it actually appears to work:
deny
message = <$sender_address> is an invalid address!
log_message = <> is an invalid address.
senders = :
i've added it into the acl_check_rcpt section (debian's exim4 config
section name which is actually acl_smtp_rcpt)
there are probably better places to put it - like in the acl which deals
with mail from - but i don't know its name. acl_mail_from, by chance?
:)
l.
On Thu, Feb 01, 2007 at 04:42:19PM +0000, Philip Hazel wrote:
> On Thu, 1 Feb 2007, Luke Kenneth Casson Leighton wrote:
>
> > HELO localhost
> > MAIL FROM:<>
> > RCPT TO:llllllllllllltotallyfakeaddress@localhost
> >
> > and _that_ was accepted (!)
>
> Instead of doing this using telnet, try using Exim's -bh debugging
> facility, possibly also with -d for additional debugging data. It will
> show you exactly what Exim is doing.
>
> --
> Philip Hazel University of Cambridge Computing Service
> Get the Exim 4 book: http://www.uit.co.uk/exim-book
--
--
lkcl.net - mad free software computer person, visionary and poet.
--
