Re: [Exim] Re: Ho hum... Blackhole Lists...

On Tue, 2002-02-19 at 15:24, Philip Hazel wrote:
> On 19 Feb 2002, Dirk Koopman wrote:
>
> > Well on further fiddling I have found out the following:-
> >
> > 1) The "a@b"@z construct appears NOT to be rejected except by the
> > "accident" that a@b isn't a valid local user.
>
> That is not an "accident". It normally IS an invalid local user. But
> that is for you to decide - at the mail standards level it is just
> another local part which is a bit odd because it contains an @
> character.
>
> > If you pass it to a smart
> > host it will happily be expanded. z can be ANY local domain whatsoever.
>
> That is the fault/problem of the smart host.
>
> > 2) The way to I have chosen to stop it is as below:-
> >
> > # this checks for nasty characters in the localpart by only
> > # checking that only [A-Za-z_.-] are there.
>
> What is the problem with just rejecting it as an unknown local part?

None, except that I don't know how to do it.

>
> > There must be some means of not having to do the above. I repeat, I have
> > receiver_verify on.
>
> Lots of sites have valid addresses containing characters other than
> those you have chosen to allow above. Just look at my own address for a
> start. Exim cannot prescribe these things.
>
> However, in Exim 4 you can reject incoming SMTP addresses on this basis
> at SMTP time by a suitable configuration. In fact, the default
> configuration does do this by default, because so many people have had
> problems. Exim 4 (in the default configuration) rejects addresses with
> local parts that contain any of @ % ! / or | at RCPT time.

So I take that if I set my 'invalid character' director to match on
these characters then that will have the effect I want in 3.33?

And there is no 'better'[tm] way of doing it (for 3.3x) than:

reject_illegal_char_relay:
driver = smartuser
no_verify
condition = ${if match{$local_part}{[\\@%!/|]}{yes}}
new_address = :fail: rejected illegal character in local_part attempt

# this director sends locally delivered stuff thru spam assassin
send_to_spamc:
driver = smartuser
transport = spam_scanner
condition = ${if eq {$received_protocol}{spam-ok}{no}{yes}}


Dirk
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