We have an Ubuntu server connected to internet and PC's with Vista installed on them. The users all use Outlook but request shared mailing lists and shared agenda.

We would like to use Zimbra server on a Linux PC to provide a solution.

My questions are:
1) Which DNS server should we use, the Ubuntu server or do we have to install BIND (or so) on the Linux PC?
2) How do we configure the MX record (depending I suppose on the chosen config)?
3) Is there anything else we should do?

Thanks in advance.