On 2007-01-20 17:36:13 -0500, Matt Sergeant wrote: > On 20-Jan-07, at 2:37 PM, Peter J. Holzer wrote: > >>Nonsense. I block all mail from <> and have done for 2 years (maybe > >>more). [...] > >>There's no harm been done, > > > >You won't get any bounces, so if one of your mails can't be delivered > >after it has left your MTA, you won't get notified. Also, if you block > >it at the MAIL or RCPT stage, SMTP callbacks (as done by Exim, > >Postfix, > >or my smtp_callback plugin) won't work and you won't be able to send > >mails to MXs which use this. > > SMTP callbacks are broken by design if they assume that a rejection > of RCPT TO <> means the domain isn't valid.
Well, a rejection of MAIL FROM:<> means that I can't send any bounces
back. That's a good reason not to accept the mail in the first place -
if the sender isn't interested in a delivery failure the message can't
be that important ;-).
OTOH, using the same technique to determine whether an email address
exists is flawed: If an address is set up only to receive mail, but it
is never used to send mail, there is no reason to accept bounces for
that address.
> But I accept the consequences of what rejecting <> does - but the
> value in accepting that mail is about as high as accepting mail
> without a Date: header or without a Message-Id header (both things I
> reject also).
I like to know when a message I send cannot be delivered, and so do my
users. Unfortunately some systems do accept mails and only then notice
that they can't deliver them, so I have to accept bounces (I could use
BATV oder SES or a similar scheme if my email address is ever abused by
a spammer, though).
hp
--
_ | Peter J. Holzer | I know I'd be respectful of a pirate
|_|_) | Sysadmin WSR | with an emu on his shoulder.
| | | [EMAIL PROTECTED] |
__/ | http://www.hjp.at/ | -- Sam in "Freefall"
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