Hello,
Is your Zimbra install failing with the following error?
IO::Socket::INET: connect: Connection refused
One possible reason for the problem is that the install scripts have trouble with servers behind a NAT.
The install scripts can't handle it if the IP of your FQDN is not an IP configured on a local network interface.
A possible workaround is to add an alternate name to DNS that resolves to your "internal" IP address for use during the install process.