We've been running our new Zimbra system for a few days and things seem OK. However, I got a returned email today with this error message:

The Postfix program

... host mxi2s.craigslist.org[66.150.243.2] said:
504 : Helo command rejected: need fully-qualified hostname (in
reply to RCPT TO command)

If I look in /opt/zimbra/conf and look at main.cf, indeed

myhostname = mail-01

Where is this being set from? Shouldn't the domain name be appended to mail-01 at this point? In the admin GUI, my Service host name is mail-01.

Our email is getting through, but maybe few are checking for the FQ hostname. Even though, I'd like it to be set correctly.

Thx in advance!