sorry, if my question sounds simple. We have zimbra on a server, which is available on public IP (not hard-firewalled, although possible to make). In the past few weeks we were blacklisted several times, but still are unable to find out "why". At this moment I just want to be sure, that we do not allow using our server as "outgoing mail server" (relay) even for our authenticated users. They may be allowed to send email from webmail, but not remotely. Is it possible or is it strongly not suggested? Can it break outlook-plugin functionality?
P.S.: is it possible to trace source of spam using entries in mysql database "zimbra_logger"? Please advice..