Re: [exim] Setting up a mailsink/blackhole?

On February 23, 2008 03:07:24 Dave Evans wrote:

>
> Depending on what other mail this box handles (for example, it will often
> need to handle its own mail, e.g. as generated by cron), you may want to
> add "domains" conditions to those routers. Currently alerts_qa@???
> (for example) would be routed to the alerts mailbox, not to google.
>

This box will never be used to deliver mail to the Internet at all. That would
be disastrous for us! I also realized that emails to alert_qa/dev would not
go to the correct mailbox, but I think it is unlikely those local_parts would
show up so I'm not too worried about that.

> > And speaking of which, I was wondering, aside from experience, is there
> > some kind of rule-of-thumb about when you want to implement something
> > whether one should use ACLs, routers or transports? I don't think I've
> > quite wrapped my brain around this yet.
>
> Transports are the methods of delivery (SMTP, maildir, lmtp, etc).
>
> Routers are used to select a transport, usually based on the recipient
> address (but as you can see you can also base the decision on other things,
> such as the sender's IP address).
>
> ACLs are primarily used to perform filtering before the message is accepted
> by Exim, placed in the queue, and delivery attempted. They can also have
> side effects, such as adding headers, or variables which are later used by
> the routers.
>
> So for example if your box knows how to deliver mail for
> "bob@???", it's the routers which decide where that mail
> goes. If it knows that "nosuchuser@???" is /never/ a
> good address, that's also the job of the routers (to ensure that the
> address is unrouteable). To decide whether or not mail arriving via SMTP
> for bob@??? should be allowed in in the first place, use
> ACLs.
>
> Does that help?

Yes, it does, thanks. The rusty cogs were starting to grind away a bit more
last night as I was thinking about all this after sending my reply email...

Thanks again!
Andrew