Zimbra webmail https error
After installing zimbra 8.8 if you try to access the webmail using the IP and https protocol you may get “Secure Connection Failed” error on your browser. To fix this you need to set the zimbraVirtualHostname and zimbraVirtualIPAddress for the zimbra domains. For example for the domain domain.local with IP run the following command.

zmprov md domain.local zimbraVirtualHostname `hostname -f` zimbraVirtualIPAddress
zmproxyctl restart

The above command should be run as zimbra user.

RRD Tool
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FireFox and Zimbra Admin interface
Zimbra 8.7 and above admin interface has an issue with firefox, if you quickly modify some settings for a user using admin interface without letting firefox load the complete page, for example changing the account status, zimbra might delete the unloaded setting for the user. So either use firefox patiently or you might want to use google Chrome which is reported better at this.

Zimbra IP change
If you want to change the IP on a running Zimbra server apart from changing the obvious things like mynetworks, zimbraVirtualIPAddress etc you might want to change ldap bind address. Zimbra ldap bind it self to the IP and if the users try to authenticate from a different IP ldap will not respond. so to fix this

#As zimbra  
zmlocalconfig | grep -i 'ldap_bind_url' #This will give you the currnet value of ldap bind address  
zmlocalconfig -e ldap_bind_url="ldap://<ip>:<port>"  
#You can also do some thing like this if you want to add mulitple IPs
zmlocalconfig -e ldap_bind_url="ldap://<IP1>:<port> ldap://<IP2>:<port>"
ldap stop  
ldap start