This all depends on your Zimbra provider. If it's an Internet Service Provider (ISP), then they should have provided you with the info necessary to setup your phone. If it's your place of employment, again, you'll need to get the info from them.
Originally Posted by poumtatalia
If you're running the OSE version as a home mail server, then you'll need to connect via POP3(s) or IMAP(s) and not Exchange.
Ben Franklin quote:
"Those who would give up Essential Liberty to purchase a little Temporary Safety, deserve neither Liberty nor Safety."