We've been using ZCS for about 2 and a half years and haven't had any problems with it. Recently we migrated from ubuntu-zimbra 4.5.18 to debian 5.0.11 with a little difficulties but clear for the end users.
My problem is that we have a mixed environment with Windows XP, Windows Vista and Ubuntu desktop 8.10 clients an with the windows machines the calendar shows the exact date and time of the server (as it should be) but with the linux machines it shows a difference of 19 hours and 30 minutes wich gives us a day difference in hour received mail. We have tried everything we can think of to fix this error but we haven't found a solution.
In the linux machines when any user logs in it automatically sets the time to +19:30 hours. In the options tab the timezone is set to Auto-Detect an it shows "(GTM+1930 Auto-Detect)". If we change this to hour local time zome (GTM-0430 Caracas). it still show the day difference in the calendar even if we log out of zimbra and log back in, and even if we reboot the computer it still shows the day difference.
We have check that the time zone in the server is set correctly. We have ntp service installed sync with our internal time server. The clients machines are set to the correct time zone using the gnome interface, the command line "dpkg-reconfigure tzdata" and also installing the ntp service to sync the time with our local time server.
We need to solve this issue as soon as possible since we use zimbra to set meeting and conferences both internal and external.
We have a plan to migrate all employees to ubuntu desktop but we can't do that until we have all our current applications running with no problems
Any help would be appreciated. Thanks in advance.