if the /etc/resolv.conf is changed to
nameserver 127.0.0.1 search domainname.local nameserver 192.168.0.1
The local dns caching server is activated (127.0.0.1) - Zimbra changes this and use the configs:
[zimbra@mail root]$ zmprov getServer `zmhostname` | grep DNSMasterIP zimbraDNSMasterIP: 192.168.0.100 zimbraDNSMasterIP: 192.168.0.1
To remove a unused server (.100)
zmprov ms `zmhostname` -zimbraDNSMasterIP 192.168.0.100
or add a new server
zmprov ms `zmhostname` +zimbraDNSMasterIP 192.168.0.1
Link: https://wiki.zimbra.com/wiki/DNS_caching_service_(dnscache)