On Fri, Sep 21, 2001 at 09:44:47AM +0200, Marc Langer wrote:
> On Fri, Sep 21, 2001 at 00:21:13 +0100, Matthew Byng-Maddick wrote:
> > > But how should I reject certain recipient addresses?
> > > I read about receiver_verify, but are feeling uncomfortable with
> > > enabling it. Are there any other possibilities?
> > Can someone explain to me what the problem with enabling receiver_verify is?
> > I can understand in a large site where your mail reception and queue-running
> > are likely to be different processes, but why does it make people
> > "uncomfortable", after all, if the verify fails, then it would fail later
> > and bounce anyway?
> I did not fully understand the concept of "receiver_verify" yet.
OK. The idea is that rather than accepting everything, and then bouncing on
delivery, you instead do the checking of whether the receiver is going to
be deliverable *during the SMTP dialogue*.
ie.
WITHOUT:
>>> 220 Exim blah blah blah
<<< EHLO my-server.domain.tld
>>> 250-Hello
>>> 250 SMTP-EXTENSION
<<< MAIL FROM:<me@???>
>>> 250 Sender ok.
<<< RCPT TO:<undeliverable@???>
>>> 250 ok.
<<< DATA
[...]
At which point you bounce the message.
WITH:
[...]
<<< RCPT TO:<undeliverable@???>
>>> 550 Address not found
> Is it sure that there are no more mails rejected than without this
> setting turned on? Especially mails from unknown hosts (without DNS
This should certainly be the case, as it should only reject stuff that would
bounce later on anyway.
> entries) must not be rejected.
Rejecting mails from hosts without rDNS is orthogonal to verifying the
recipient in the dialogue.
MBM
--
Matthew Byng-Maddick <mbm@???> http://colondot.net/
