I have the open source version working, and I'm liking it. A real sweetener is that there are already people using Zimbra's LDAP with a Samba domain. This is important to me. I do, however, think that if we go for it we will be paying for the network edition, mainly for the storage and backup features.
I've been thinking of how to structure this, and I would like to describe my environment and my goals, and get the experts' input.
We have four sites. There are about 40 users at the main site, and about 15 each at the other three. There is 768Kbps bandwidth between the sites - a site-to-site VPN over fractional T1s. The main site has a full T1.
My primary goals are that the message stores be accessed at LAN speed by all users, and that outgoing messages be accepted at LAN speed from all users.
So I'm assuming there should be a Zimbra Mailbox server at each site, a Master LDAP server at the main site, and LDAP replicas at the three other sites. Not sure about where the Zimbra MTAs need to be.
In my current setup (qmail/Dovecot/Perdition) I accept all incoming mail on a DMZ network at the main site, which is then forwarded to the IMAP server local to the recipient.
There's also a Perdition IMAP proxy in the DMZ that allows Internet IMAPS clients to connect to my internal Dovecot servers.
I would like to keep the general flavor of my current setup, but step up to Zimbra, with its directory service/GAL, Calendaring, chat, shared docs, etc.
Thank you in advance for your guidance and advice.