Hello Experts, I am facing an issue with the DAG IP conflict on my Exchange servers. We have two Exchange 2010 servers and 1 file share witness. They all are on VMWARE, from last few days I am receiving event id's 4199 stating the IP conflict with the MAC address but when I searched the MAC it was my MBX01 server and after 1 day I again received the same alert on MBX02. So my DAG ip is conflicting with my own Exchange server MBX01 and MBX02. I have checked the registry entries for the my DAG ip but found nothing. Please help how can I get rid of this problem.

Hi It seems to be network issue. 1. Install the following hotfix 2470853 on both cluster nodes, as there have been some critical updates to TCP/IP components on Windows 2008 R2 that addresses network connectivity issues. http://support.microsoft.com/kb/2470853 2. Disable TCP Chimney, RSS and NETDMA as per Q951037 on all cluster nodes.Information about the TCP Chimney Offload, Receive Side Scaling, and Network Direct Memory Access features in Windows Server 2008 http://support.microsoft.com/kb/951037/en-us 3. Increase the UDP package interval and threshold. This will make cluster be more tolerable for the network package drop or package delay. Steps as below: Open cmd.exe, run the below commands: cluster /prop CrossSubnetDelay=4000 cluster /prop CrossSubnetThreshold=10Terence Yu TechNet Community Support

Hi It seems to be network issue. 1. Install the following hotfix 2470853 on both cluster nodes, as there have been some critical updates to TCP/IP components on Windows 2008 R2 that addresses network connectivity issues. http://support.microsoft.com/kb/2470853 2. Disable TCP Chimney, RSS and NETDMA as per Q951037 on all cluster nodes.Information about the TCP Chimney Offload, Receive Side Scaling, and Network Direct Memory Access features in Windows Server 2008 http://support.microsoft.com/kb/951037/en-us 3. Increase the UDP package interval and threshold. This will make cluster be more tolerable for the network package drop or package delay. Steps as below: Open cmd.exe, run the below commands: cluster /prop CrossSubnetDelay=4000 cluster /prop CrossSubnetThreshold=10Terence Yu TechNet Community Support

Thanks Terence.. Still the same after applying this.... Can we change the IP address of the DAG and check..... is this feasible and good move..?