How to set up calDav & cardDav on iPhone 4s for Tier3 Consulting customers using contacts & calendars on our zimbra servers:

Go to settings and select mail accounts:

For the type of Mail Account, Select OTHER

input your server and user information for Contacts (cardDav) or Calendar (calDav)

mail.YOURDOMAINNAME.com (or net as applicable)

your USER NAME is USERID@YOURDOMAINNAME.com (sampleuser@tier3consulting.com)

make sure you use SSL on port 443

NOTE:  Some lessons learned with this version of Zimbra [future versions are slated to address some of these issues].  Using NOTES from email settings creates an email folder in Zimbra which you can VIEW only (i.e. copy/paste) but you cannot edit.  Zimbra TASKS sync with your iPhone REMINDERS.  If you share Contacts via Zimbra, they will not appear in your iPhone, nor will any embedded contact folders.  Shared calendars do appear on your iPhone.