On 16/10/2007, Robert Felber <[EMAIL PROTECTED]> wrote: > On Tue, Oct 16, 2007 at 08:36:11AM +0200, Andreas Fuchs wrote: > > 2. in the log i have quite often the following entry > > > > Oct 16 08:30:53 schilt postfix/policyd[20148]: decided action=DUNNO NULL > > (<>) Sender; delay: 0s > > I don't know exactly how to debug them, the process number is repeating > > quite often, > > any ideas? > > That are NULL-sender (mainly generated by DSN). You MUST let pass them. If > the NULL Sender try to deliver to non-existing users then reject all mail > for non-existent users. > >
Why MUST they pass? From what I understand of our favourite RFCs, DSNs should not be treated any differently from other normal traffic. Section 4.5.5 of RFC2821 states only these: "If the delivery of such a notification message fails, that usually indicates a problem with the mail system of the host to which the notification message is addressed." Which would be the same for any other type of message.. and: "systems SHOULD NOT reply to messages with null reverse-path" Which is no surprise either. Maybe I'm missing some other detail.. But, I do know that one spammer technique is to populate both the From (Return-path) as well as the To with their intended spammee database and almost rely equally as much on DSNs to deliver payload. (which is why DSNs these days should not contain message bodies). So, why allow DSN's to violate all kinds of policy, even their client IPs appearing on SBL+XBL, etc.? I don't think that's right. regards, Riaan ____________________________________________________________ Policyd-weight Mailinglist - http://www.policyd-weight.org/
