In exchange2010 mail system, a DAG is created to support high availability of mailbox database, each db has two copies which are located in mailbox server respectively.
Sometimes a dialog box appears in both servers, which indicates that windows detect an IP conflict
Because the network connectivity is not stable, failover cluster detects the failure and try to bring online IP resource in the other node, but the original node does not release the IP resource immediately, so windows system detects IP confliction.
In order to reduce IP confliction, modify IP resource properties as follows
Step 1. Check IP setting of all NICs in both server, all IP addresses are static, identical and no confliction.
Step 2.check DAG IP, because DAG IP is a dynamic IP, and attached to a server according to failover cluster status
Step 3. Query failover cluster manager log, there are records of network disconnection and IP address resource restart
Exchange2010 DAG is based on failover cluster manager, pay attention to failover cluster status, and make sure cluster is running properly