I recently installed ZCS 4.5.9 (OS) on an Ubuntu 7.10 server (success coming eventually after editing DISTRIB_VERSION to 6).
I now have the odd situation that when our users (with addresses of the form email@example.com) attempt to use an email client (Outlook or Thunderbird) with an IMAP-configured account to send mail to addresses outside our domain (of the form firstname.lastname@example.org), the following error message appears:
An error occurred while sending mail. The mail server responded: <target email address>: Relay access denied. Please check the message recipients and try again.
Having thus failed to send, if they then save the message in their Drafts folder, and open up the Zimbra web interface at mail.ourdomain.com and simply send that same saved message, it flies the coop without so much as a whimper.
Is there some setting I have missed that would allow the email client attempt to succeed?
On Microsoft Exchange I could make settings that allowed relaying from specified IPs (I've found that setting on Zimbra and made it accordingly) and FROM AUTHENTICATED USERS. I can't find the similar setting on Zimbra.
I can't specify all the thousands of potential IPs from which our authenticated users may want to send messages to addresses outside our domain ...
Thanks in advance for any help.