SQL AG: Cluster IP address resource cannot be brought online because a duplicate IP address was detected on the network. Please ensure all IP addresses are unique.

Question

I built a SQL Cluster with always on availability groups, I am seeing the following error on the events

Cluster IP address resource cannot be brought online because a duplicate IP address was detected on the network. Please ensure all IP addresses are unique.

Cluster IP 10.1.10.91

You see in the image 2 that shows roles, the cluster IP is popping up under AG resource and its failing to bring it online. Can I remove this?

Answer 1

Hi @Sue_8827 ，

As the error message said, the virtual IP of the cluster should be unique, please check your virtual IP address, if the IP address is duplicated, you can consider changing the IP address, right-click the IP address, choose Properties, you can see the Static IP address and change it to make sure this new IP is unique on the network, if you change any of the settings, try to bring the resource online first
https://www.mssqltips.com/sqlservertip/4220/change-the-virtual-ip-address-for-a-sql-server-failover-cluster/

-------------

If the answer is the right solution, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Answer 2

cannot be brought online because a duplicate IP address was detected on the network

You get a clear error message, so check your network if the IP address is used elsewhere, e.g. ping the IP address with resolving to machine name.

Answer 3

Hi @Sue_8827

No, you can't just delete the IP address on the AG role.

But you can remove the IP address from the listener of the AG and add another free IP address to the listener.