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Postfix Archives: Re: Local mail being duplicated

Re: Local mail being duplicated

Andrew McNamara (andrewmconnect.com.au)
Fri, 12 Nov 1999 13:44:58 +1100

>> The virtual file would almost do everything I want - except that it
>> can't cope with include files (I can live with it not doing program
>> aliases). Would it be reasonable to add this functionality?
>
>Interactions with user-land must be done with the proper privilege
>- so this would require root privilege some of the time. I'm not
>too eager making more parts of Postfix privileged.

Ah - I wasn't suggesting sendmail compatible includes - I'd be quite
happy reading the list with standard postfix permissions. The only
problem is that you could be reading a potentially large list - if you
chose to defer the loading of the list (as sendmail does), then it
wouldn't work in a chrooted environment (I think)?

>Set up an owner-whatever alias. I have suggested this before.

We're talking about hundreds of aliases that will need this treatment
(every project, groups and sub-groups in the company, etc). That's okay
- but it will take time.

But - my point was, this is a work-around: other people are going to
have this problem and will bother you for eternity... 8-)

>> We almost need to distinguish between "simple" forwards and complex
>> aliases, where simple would be done directly in the local agent (risk
>> of duplicate delivery) and complex would be pushed back into the queue
>> (performance cost). I'm racking my mind to think of a way to draw the
>> line between the two.
>
>The problem is not just a matter of simple versus complex. With a
>composite alias "foo: bar, foo", sendmail will deliver to both
>users foo and bar. If Postfix doesn't, someone will lose mail.
>
>> Maybe it would be enough to deliver direct when an alias only has one
>> right hand side, or there was a program or include on the right hand
>> side, with other cases treated as a forward/requeue?
>
>An alias may have multiple right-hand sides of mixed types.

Hmmm. I suspect we're not talking about the same thing, or I'm just
not understanding something.

There are two behaviours currently: the "recursive" default behaviour,
and the "forward" behaviour, which is triggered by various things
(nexthop not local, primarily).

What I'm suggesting is that we make a hybrid - recurse building a list
of recipients for forwarding/requeuing (and performing local delivery
when it makes sense), but stopping short of any aliases with programs
listed on the RHS.

I realise this will be slightly non-obvious, but I'm not happy with the
alternative (because the stuck e-mail will be delivered indefinitely
until a sysadm intervenes).

>But it can be argued that "deliver to all right-hand sides" before
>retrying is better.

8-)

This would make us much happier. The event that set all this off was a
message from our system monitoring that should have gone to the on-call
pagers, but got stuck in the "broken mailbox hell" - I've had people
bitching all week about postfix, not to mention the bind security
alert. 8-(

There was an amusing moment, however, when a message about "telephone
sanitisers coming on Friday" was repeated dozens of times - I thought
they only existed in the pages of Douglas Adams - I'm tickled pink to
discover we employ them.

 ---
Andrew McNamara (System Architect)

connect.com.au Pty Ltd
Lvl 3, 213 Miller St, North Sydney, NSW 2060, Australia
Phone: +61 2 9409 2117, Fax: +61 2 9409 2111

This archive was generated by hypermail 2.0b3 on Thu Nov 11 1999 - 20:45:11 CST