Mailscanner watermarks and compatibility with other systems

[Jonas Akrouh Larsen]

Yep

We are doing as JP writes, you enable the recipient fitler in exchange,
making exchange reject any invalid/unknown recipient. And make exim (or
whatever mta ur using) do recipient callout, meaning it connects to the
backend exchange and checks (via smtp) if the user exists.

It works great, and you do not have to import any userlists or open for ldap
or anything similar.

So that's definitely what you want :)

Cheers
Jonas

> So you got a local database of all valid email adresses on each domain
> at the MS installation? if so I want to know how you implemented this,
> as you are saying that you do not control all systems ? Do you sync
> the exchange user db ?

With Exchange 2003 and a decent MTA in front there is no need for that.
Teach Exchange to only accept valid e-mail addresses (no problem with
Exchange 2003, easy task with addon tools for exchange 2000 and maybe
5.5). Then use whatever does recipient-callouts (exim has this builtin,
postfix too AFAIK, there are milters for sendmail that do this).
Finished.

Regards,
  JP