Postfix Address Verification

[Rob Sterenborg]

> Mail from the internet hits the "Gateway" machine with
> MailScanner and postfix. The clean mail is then forwarded to the
> "Hub" machine, running windows and Mail Enable Enterprise.

[...]

> So, as per documentation (on the MailScanner docs, Postfix
> website), I set up verification on the Gatekeeper machine, such
> that when a mail comes in, postfix looks in the transport map,

I didn't see this in the doc, so I'm not sure if you did this..

If your Postfix is a relay for your Windows mailserver, Postfix *must*
know which domains to relay for. Typically, you configure Postfix for
this using the relay_domains parameter which holds either all relay
domains or points to a file/db that holds the relay domains.
relay_domains should *only* contain relay domains, and mydestination
should -of course- *not* contain any relay domains.
See: man 5 postconf.

> then queries the Hub machine as to whether the mailbox exists or
> now. Then the Gateway machine can reject the mail "at the door"
> (solving bandwidth, load and bounce issues).

Personally, I think you shouldn't bother your Windows mailserver with
address verification.
I know nothing of Mail Enable Enterprise, but perhaps you can, like with
Exchange, export a list of all know email addresses using some script
(perhaps LDAP?), reformat this list into something postmap can use to
create the hash file or put it in a database, and configure Postfix to
query that list/db using relay_recipient_maps.

That way you may not have all email addresses at any given time but if
generating the email address list isn't generating too much load you can
schedule the script to run more frequently so you won't run far behind.
This all depends on your needs however.
The positive side on this is that when you get flooded with email, at
least the Windows servers don't get DOS-ed with verification requests so
your corporate/internal email doesn't suffer from it.


Grts,
Rob