we have been using Zimbra for over a year now and are very happy with it.
So far, we have only ever used it on our internal (local) network.
Users have asked if they could view their Zimbra account from home, including the Calendar but I have been reluctant to reveal it to the Internet like that. I have just been using Roundcube on our webserver pointing at our Zimbra server, just for mail.
We have now inherited a Sonicwall pro 4060, which is a really nice firewall I believe and this combined with us signing up to MessageLabs for Email filtering makes me wonder if now might be the time to allow more access to Zimbra from outside.
So, basically, how do people do this? Are there any tips or or a guide on securing Zimbra and it's Services before opening it up? (I couldn't find anything in the Wiki)
I guess will probably put the Zimbra server in a DMZ along with a few other servers and allow direct access to it through a port number.
We are authenticating with Active directory though, would I be better just using the local Zimbra authentication or perhaps an LDAP server?