Re: [exim] :fail: & :blackhole: implementation

--On 22 January 2007 17:01:21 +0200 Michael L Griffin <milegrin@???>
wrote:

> Greetings
> On 22/01/07, Ian Eiloart <iane@???> wrote:
>> --On 22 January 2007 15:58:35 +0200 Michael L Griffin
>> <milegrin@???> wrote:
>> >
>> > 1) From my reading on the archives, :blackhole: is only taken into
>> > account after processing the mail which is a waste of resources. Is
>> > there a way to blackhole directly after receipt before processing?
>>
>> Don't do that. If you don't want an email, then use "deny" in an ACL
>> before the DATA phase. That way, if the sender is a real person, they'll
>> get a failure notification. If the sender is a spambot, then the spambot
>> will blackhole the message.
>>
> I have approximately 45 domains on my little server and :blackhole: is
> only used on individual accounts as specifically requested (eg dude
> has left and they no longer the mail sent his address and don't want
> to bounce it) and it is easier to simply blackhole. Any ideas as to
> howto implement your suggestion directly after SMTP time before
> processing?
> (I discourage the use of blackhole but clients are always right (c:} )

You should use a recipient ACL to check whether the address is deliverable,
with a callout. You can customise the content of the 5xx reply. Or, I guess
you could use the same lookup as you do for routing, and if the result of
the lookup is ":blackhole:", then "deny" the message.


>> > 2) On my exim3 system, I can fail a message with a custom fail message
>> > eg : :fail: Sue has left - please speak to Mary
>> > This would generate a 550 with the specified message. On the Exim4
>> > system, it generates teh 550 but ignores the message so a generic 550
>> > is received and the custom message is ignored. How do I get the
>> > :fail: bounce to include the custom message?
>> >
>> > As an aside - would it be possible to change the bounce subject? If
>> > so, how?
>>
>> You should NOT be generating bounce messages if you can help it. Usually,
>> they will go to the innocent owner of a spoofed email address.
> Correct, BUT, I have to cater for the legitimate bounces.
> This is especially useful when addresses are no longer valid and an
> announcement in the form of a bounce is used to give an alternate
> address. I prefer this over blackholing as the sender of legitimate
> mail can resend to the correct address.
> It is also very useful when used in conjunction with a "catchall"
> where legitimate mail is delivered and all mail to non-existent
> addresses is bounced containing a obfuscated valid contact address and
> message (I can customise the contact address per domain)

Well, if you bounce spam, you'll end up getting blacklisted sooner or
later, so see the comments above. Again, you could do a similar lookup, and
use the result to set the rejection message.

--
Ian Eiloart
IT Services, University of Sussex