Disallow search engine index in Zimbra robots.txt

Disallow search engines to index your Zimbra

Change robots.txt to Disallow from the default
value of Allow with one command. 

Step 1: Run as Zimbra user

zmprov mcf zimbraMailKeepOutWebCrawlers TRUE 

and the value of your https://www.domain.com/robots.txt

will change from Allow to Disallow