Invitations with ZCS w/o MX records

[bakreule]

Hello all,

I've been asked to install a zimbra suite that might be a little different from the standard install. For right now they send/receive email using their hosting provider, meaning they're not ready to move their MX records to the Zimbra server. They want to:

-Send "internal" email/calendering requests using ZCS
-Send external email/calendering requests using their hosting email (pop)

So they would have two accounts using Zimbra desktop: their internal zimbra email and their external email by pop.

My question is, is this something that Zimbra easily supports? More specifically:
-What happens if they create a RDV and invite one internal collaborator and one external client? Because any accept/reject replies will be coming from different accounts, will everything be properly put into the right calendar?
-Does Zimbra Desktop handle the sending/receiving of RDV invitations to external mail clients? Will Outlook handle an invitation request sent by Zimbra desktop?

Thanks for any thoughts on this matter....

[phoenix]

You need to have valid DNS A & MX records (and hosts file) in place for Zimbra to work correctly - it's needed by Postfix for mail delivery. If you're behind a NAT router or firewall you'll need a Split DNS set-up.