We are currently trialling Zimbra and I've noticed that in the Global Settings where the outbound SMTP service is set up, there doesn't appear to be a facility for a user id. and password, in other words, SMTP authentication. All I can seem to find is a host name and a ':' box for the SMTP port to send to.
There are options to use MX lookups, but we shall need to use authenticated SMTP if we decide to go live.
Can we do this?