What is the different between this 3 method?
1. Administration Console and CLI Certificate Tools
2. Recreating a Self-Signed SSL Certificate
3. From Release Notes for Zimbra™ Collaboration Suite 5.0.18 Open Source Edition
Verify Certificates Expiration Date
ZCO 5.0.x requires a valid self-signed or commercial SSL certificate for communication between some components. The self-signed certificates that are automatically created by the ZCS install have a default expiration of 365
If you have an ZCS installation that is over one year old and are using selfsigned certificates, your certificates will need to be updated either prior to the upgrade or immediately following the upgrade.
After you upgrade, the following commands run as the zimbra user will regenerate the self-signed SSL certificates:
• sudo zmcertmgr createca -new
• sudo zmcertmgr deployca
• sudo zmcertmgr deploycrt self -new