I have a real problem, somehow my two Zimbra mailservers on the same network are using eachother to relay messages.
There are no settings between the two mailservers and they do not have any shared domains.
Data from yesterday are:
zimbra1 sent ~6k messages of which 153 went to zimbra2 for relay.
This is done seemingly on random. Sometimes messages from recipientA to recipientB use zimbra1 and sometimes zimbra2.
Zimbra 1 is ZCS 8.0.2
ZImbra 2 is ZCS 8.0.5
What can cause such behaviour? Thanks