After installing Zimbra I have a web client running on port 8443 and 8080. On the machine itself I can access using
http://localhost:8443
I want to allow users access to this web client via a reverse proxy server. The root web context is already used so I want to serve the web client through a folder. So for example
https://www.mydomain.com/webmail
which is proxy for
https://localhost:8443/webmail
For this setup I think I need to change the web context of the Zimbra web client so that it will run from
https://localhost:8443/webmail
and not
http://localhost:8443
Zimbra CLI allows change of port but I did not find change of context. Is this possible? How do I do it?
NO, that configuration doesn't exist in zimbra. HTTP service on zimbra can't run in web context like above.
Instead change Zimbra web context, you can use Apache for alter zimbra response using mod_proxy_html.
This solution based on this answer and this blog.
For performance concern, I suggest you test that configuration. The biggest bottleneck will be in mod_proxy_http because this module will perform search and replace in every request. See the comment about it performance in here.