CalDAV with Leopard iCal


Zimbra 5.0 Supports the CalDAV standard. This allows users to publish and subscribe to calendars, share them collaboratively, synchronize between multiple users and synchronize between multiple devices. The CalDAV standard is an implementation of iCal on a WebDAV server.

CalDAV is a protocol allowing calendar access via WebDAV. CalDAV models calendar events as HTTP resources in iCal format, and models calendars containing events as WebDAV collections.

When using CalDAV, all of the user's calendars are added to iCal.


  1. Zimbra Collaboration Suite 5.0 RC2 or Higher
  2. MacOS 10.5 or Higher

Zimbra Connector for iSync

The Zimbra Connector for iSync syncs Zimbra calendars to iCal for Tiger (10.4) and Leopard (10.5). The sync is done using SOAP instead of CalDAV -- so if you care about sync'ing contacts in addition to calendars, choose iSync. Otherwise, don't bother with with it, and setup your calendars as CalDAV calendars in iCal.


In Leopard (10.5), open iCal and go to: Preferences > Accounts

  • Click the + (plus sign) to add an acocunt
  • Enter a description; and enter the Zimbra username and password
  • Click the arrow to expand "Server Settings"
  • For the Account URL enter: http(s)://<server>, in other words iCal supports CalDAV principal concept so you'll notice that iCal will expand it to say: http(s)://<server>/principals/users/<username>

Note: You must not append anything after the servername when using iCal. There is an iCal bug that will cause it to fail. The URL should look like: and not

  • You're done -- hit Add.

Errors due to self-signed certificates

If your Zimbra server is using a self-signed certificate the subsciption to the server may fail with error -9813. In this case browse to your Zimbra server via Safari (using https) - accept the offered certificate permanently in all instances and close and reopen iCal.


Older MacOS

iCal on Tiger and older release only support ics import and export, not the full CalDAV. The ics import mode is not compatible with CalDAV at all, and the usage is completely different.

In order to use ics import mode, first the user needs to export the calendar folder as ics, save to a file, then import the file into the target calendar application. Using ics import mode, the changes made to the 3rd party calendar is saved as a local copy, and does not automatically synchronize with Zimbra server.

When using CalDAV client, the changes are immediately saved to the server, unless the client is run in the offline mode. There is no manual file based synchronization needed as with ics import mode.


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