I've got a single Zimbra server with one domain working fine. The time has come to add several new domains to this server and I want to make sure I understand the necessary configuration and implications.

Btw I read this thread where a user asks many of the things I want to know, but not all the questions were answered.

In order to keep things clear the server is behind NAT with split-dns configured and the current domain is example.com. I want to add a second domain example2.com and it is important that the domains are completely separate. I will be the only admin of the server and domains.

1. Creating a new domain is as simple as going to the admin console and under Domains going through the "New Domain" wizard, right?

2. Is example2.com completely separate from example.com, e.g. SPAM, HAM, admin, wiki accounts, GAL?

3. External DNS: I create an MX record for zcs.example2.com and an A record for the IP address of the server just as I did for the first domain?

4. Internal Split-DNS: I modify, /etc/hosts, /etc/resolv.conf to add example2.com. Also, make changes to bind to add a DNS zone /etc/bind/named.conf.local and /etc/bind/db.example2.com.

5. SSL certificate: Right now have a self-signed cert for example.com, but looking at the wiki and some other threads I need to create a new cert for example2.com, so that the right cert is loaded depending on which domain accesses webmail and imaps.

6. Will emails that originate from example2.com show any signs in the header or otherwise of coming from server zcs.example.com. Is it better to get a third domain name that is solely used as the default domain or is this pointless?

7. Do I need to install the proxy?

8. I'm not clear on virtual hosts, but is this required or recommended for multiple domains on a single server?

I don't know if there are any other things to consider before I add domains, so please let me know.