Currently i have my server running the webpage, email and VoIP services in it, but i have the mission of installing the zimbra server on it, but i know, (i have already installed Zimbra in another server but this is the very first time im doing this), that zimbra comes out with the apache server and dunno how should i configure this, also the server is running firestarter, because this is also the LANs gateway to the internet.

As many of you have realized this is a hard work and i need a lot of help, thanks.