I work for a hospital whom internet access does not include any incoming mail relay.
So, actually, every user use an Outlook that was setup to directly send and get mails. As you understand, every Outlook client directly sends its mails to a SMTP server, and gets its mails directly from a POP3 server.

I just installed ZCS 6.0 OpenSource. How do I have to setup Zimbra to be abble to get everyones mails, and send outgoing mails ? Can Zimbra do that ?