This is the output (tail -f /var/log/zimbra.log) when issuing zmcontrol status:
Jun 19 19:22:29 zimbra slapd[4727]: conn=22 fd=8 ACCEPT from IP=10.1.20.61:32871 (IP=0.0.0.0:389)
Jun 19 19:22:29 zimbra slapd[4727]: conn=22 op=0 BIND dn="uid=zimbra,cn=admins,cn=zimbra" method=128
Jun 19 19:22:29 zimbra slapd[4727]: conn=22 op=0 RESULT tag=97 err=49 text=
Jun 19 19:22:29 zimbra slapd[4727]: conn=22 fd=8 closed (connection lost)
And this for zmcontrol start
Jun 19 19:23:33 zimbra zimbramon[9318]: 9318:info: Starting services
Jun 19 19:23:33 zimbra slapd[9359]: @(#) $OpenLDAP: slapd 2.3.21 (Apr 27 2006 13:51:14) $ root@build.liquidsys.com:/home/build/p4/CRAY/ThirdParty/openldap/openldap-2.3.21/servers/slapd
Jun 19 19:23:33 zimbra slapd[9359]: daemon: bind(7) failed errno=98 (Address already in use)
Jun 19 19:23:33 zimbra slapd[9359]: slapd stopped.
Jun 19 19:23:33 zimbra slapd[9359]: connections_destroy: nothing to destroy.
Jun 19 19:23:38 zimbra slapd[4727]: conn=23 fd=8 ACCEPT from IP=10.1.20.61:32874 (IP=0.0.0.0:389)
Jun 19 19:23:38 zimbra slapd[4727]: conn=23 op=0 BIND dn="uid=zimbra,cn=admins,cn=zimbra" method=128
Jun 19 19:23:38 zimbra slapd[4727]: conn=23 op=0 RESULT tag=97 err=49 text=
Jun 19 19:23:38 zimbra slapd[4727]: conn=23 fd=8 closed (connection lost)