Personally, I would look at using ORF w/IIIS SMTP.
http://www.vamsoft.com and IIS SMTP to provide this as a backup MX solution.
You can use LDAP etc.
--
Best regards,
Steve Schofield
Windows Server MVP - IIS
http://weblogs.asp.net/steveschofield
"Andrea" <noreply.DeleteThis@nospam.net> wrote in message
news:biMki.49696$y05.41878@tornado.fastwebnet.it...
> Hi,
> how can I configure an IIS SMTP Server to act as backup mx of multiple
> smtp domanis?
> Thanks a lot.
>
>