Hi, new Zimbra user here. So far, love the product - Kudos!

I have three questions:

1) I'm using Zimbra on a home server to serve up mail for my family. Perhaps a little overkill, but hey, live is short . How do I obtain a registration/license key for the open source version?

2) The web interface for users and administration are working great. But oddly, when I try to use a client to receive mail via POP, I can't seem to connect. The ports are open, accounts are created w/know passwords (logon name and pw work via the web client), etc. I must be missing something easy and obvious. I think it has something to do with "TLS mode" as here's what I'm getting:

Unable to send or receive messages for the Home (mail) account. An incorrect e-mail user name was entered. The next time you send or receive messages, you'll be asked to enter your user name and password for this account.

Server Error: 0x800CCC90
Server Response: -ERR only valid after entering TLS mode
Server: ''
Windows Live Mail Error ID: 0x800CCC91
Protocol: POP3
Port: 110
Secure(SSL): No

3) I'm running my server at home behind a router that obtains a dynamic IP. I've got everything worked out for DNS, routing and a consistent hostname, so all is there well. What my problem is, is that certain hosts reject email from private IP's. What I would like to do is relay my outbound mail to my IPS's SMTP server. I believe I've found where to do this via Relay MTA for external delivery, but it's telling me that "Value does not match valid value". Any ideas?

I know these are pretty simple issues and it shows I'm no email administrator. But I'm learning as I go and again, really like the product.

Thanks in advance.