Subject: R6 as a powerful front-end to R5 mail/application server ?
No.
But why one earth would you want to, even if you could? There is no reason not to upgrade your primary server now to D6, given that it is now up to it’s 3rd maintenance rev, and is officially one version behind the latest stuff.
…has chosen to deploy a new ND6.5 external SMTP server, mainly for using RBL blacklisting etcetera. But they kept their internal apps/mailserver on R5 for now, because of some applications that need to be thoroughly tested before migrating them to ND6.5.
An R5 server can use an ND6.5 Domino Directory design, so that’s not a problem too.
Remember, the IM integration is client-side, you don’t run sametime on the ND6.5 box. That’s not going to eat resources.
I’m running ND6.5 at home on a 445 mhz PIII, 196MB RAM machine and it works ok, but I wouldn’t advice that if you’re going to receive more than one email message per minute
You’re not going to be journalling mail that is exchanged between your users in that configuration. You’ll only retain mail that comes through the gateway in its routing. Same with rules.