Free/Busy Information in Outlook
If you are using https with a valid SSL Certificate (commercial certificate) then you will not face any issue to access Free/Busy Information in your Outlook but if you are using https without a valid SSL Certificate (commercial certificate) on the server free/busy information will not get fetched you will get an error. It should be possible to cause Outlook to trust the self-signed CA cert from the Zimbra server by importing it into Outlook.
Obtain Self-Signed Certificate
First you will have to obtain the self-signed certificate from the server. The certificate is in the form or PEM file, which cannot be installed on the windows system so we need to convert the certificate file.
For this you will have to follow the steps mentioned below: -
1. Log on to your server as root and go to the directory "/opt/zimbra/ssl/zimbra/ca"
2. Run the command: -
$ openssl x509 -in ca.pem -out cacert.der -outform DER ( as root )
This will generate a file called cacert.der in the same directory. Copy this file and store it on the windows system on which you want to import the certificate.
Install the Certificate
Once this certificate is copied on the system you need to follow few steps so that the certificate is installed.
There are two different methods for Windows XP system and Windows Vista system.
Method for Windows XP
1. Double click on the file cacert.der.
2. A popup will occur where you will see a button called "Install Certificate", click on the button and install the certificate, allow outlook to select the store path of certificate automatically.
3. A warring message will appear which you need to accept in accordance to allow access to the server to which the certificate belongs.
4. Once the installation is done, restart that system. After reboot, open Outlook and check, you will be able to see the free/busy information.
Method for Windows Vista
1. Close Internet Explorer if it is open.
2. Enter the MMC command at the Run prompt. This will cause Windows to load an empty Microsoft Management Console.
3. If you receive a security warning, click the Continue button.
4. Select the Add / Remove Snap-In command from the console's File menu.
5. Choose the Certificate option from the list of available snap-ins, and then click the Add button.
6. Windows will display the Certificates snap-in page. Choose the Computer Account option, and click the Finish button.
7. Choose the Local Computer option from the following screen, and click Finish, then OK.
8. Now, navigate through the console tree to Certificates | Trusted Root Certification Authorities | Certificates.
9. Right-click on the Certificates container, and choose the All Tasks | Import commands from the resulting shortcut menus.
10. Windows will now launch the Certificate Import Wizard. Click the Next button to bypass the wizard's Welcome screen.
11. When prompted, enter the path and filename of the certificate that you want to import. If you don't know the filename off the top of your head, you can use the Browse button.
12. Click Next.
13. On the following screen, make sure that the Place All Certificates in the Following Store option is selected and that the Certificate Store field reads: Trusted Root Certification Authorities.
14. Click next, then Finish.
15. You should see a message telling you that the certificate has been imported. Click OK to close this message. The certificate should now appear in the console's Certificates container.
16. Close the console.