How-to verify valid internal email addresses --- up front

[Glenn Steen]

On 07/11/2007, W S <whatisee1 at yahoo.com> wrote:
> Folks,
> I have this Hub, up in front, which process all incoming emails (running
> Postfix and MailScanner). This Hub is bluntly accepting ALL emails from
> outside and runs every single email thru MailScanner (ClamAV, Spamassassin,
> RBL, DNSBL etc) and relaying all JUNK to another internal email server.
> Now, is there any way to build some sort of MAP or database file (btree,
> hash…) from valid internal email addresses and set it on the Hub in order to
> reduce the queue?
> Regards,
> --W.S.
>
Apart from the excellent advice you already got, there is a bit on
this in the wiki/MAQ:
http://wiki.mailscanner.info/doku.php?id=maq:index#using_with_exchange_domino_etc
http://wiki.mailscanner.info/doku.php?id=documentation:configuration:mta:postfix:how_to:reject_non_existent_users#rejecting_unknown_non-local_users
(watch out for linewrapping... two separate links above;-).

These methods are mostly for situations where you cannot get the
destination MTA to reliably reject invalid/unknown users, or where you
don't want to put the pressure of recipient address verification (as
described in the link Jay gave you) on the downstream server.

Inventing your own method via ldapsearch or whatever is usually
trivial... All the map need be is a list of valid email addresses and
a "1" or "OK" or similar (the "key" doesn't really matter, just need
be there:-) ... something like:

user1 at example.net 1
user2 at example.net 1
...
userN at example.net 1

... hash that, use it in the relevant recipient_maps setting ... and
you are good to go;-) ... The links above might be a bit more
verbose:-D

Cheers
-- 
-- Glenn
email: glenn < dot > steen < at > gmail < dot > com
work: glenn < dot > steen < at > ap1 < dot > se