Here is what I am trying to setup with ZCS : I would like Zimbra web UI (installed on zimbra.example.com server) to access external mailboxes located on remote Postfix server(s) (let's call it remote.example.com).
To test the solution, I have created a user and I attached him an external account. All is right : the external account has it's own folder, it can get e-mail from IMAP mailbox on remote.example.com and it can send e-mail via that server (added zimbra.example.com IP in remote Postfix "mynetworks").
The problem : it seems that Zimbra external account can only "read" the distant IMAP mailbox. When I save a draft of send an e-mail, it is never written into the IMAP server, only as Zimbra local data.
So, please, is it possible for Zimbra to act as a standard client with remote IMAP mailboxes ? Like Thunderbird for example.
I saw that post giving a negative answer : "Is that possible to use Zimbras only as an IMAP client of an external MTA?"
Is that possible to use Zimbras only as an IMAP client of an external MTA?
But what I do not understand is why Zimbra seems to be able only to check IMAP with my setup. Is it a real limitation of the product ?