Failover Clustering - Duplicate IP - Error 1049

Lanky Doodle 191 Reputation points


We are trying to create an AlwaysOn Availability Group in SQL Server. As far as we are aware, the IP we are trying to use for the Listener is not in use - ping doesn't reply (but I generally appreciate that could be because ping is blocked), it's not listed in DNS. This has so far happened with 2 different IPs. Our IP asset register has nothing listed using these IPs, which is why we assigned these IPs for the Listeners in the first place!

However, the AG Wizard fails specifically for the Listener creation. Checking both Failover Cluster Manager and Cluster.log, it's because of a duplicate IP. Everything else as far as creating the computer object in AD works (we have setup the proper permissions to allow the Windows Cluster AD object to create descendent objects), if we use an IP not in use.

We've tried this same IP in different SQL Server instances across different Windows hosts and it's the same result.

So I'm trying to find out what method Failover Clustering uses to determine if an IP is in use before bringing something online, because all of our internal checks show they're not in use!


Windows Server Clustering
Windows Server Clustering
Windows Server: A family of Microsoft server operating systems that support enterprise-level management, data storage, applications, and communications.Clustering: The grouping of multiple servers in a way that allows them to appear to be a single unit to client computers on a network. Clustering is a means of increasing network capacity, providing live backup in case one of the servers fails, and improving data security.
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  1. Limitless Technology 38,451 Reputation points


    Thank you for your question and reaching out. I can understand you are having issues related to Cluster duplicate ip.

    1. Expand Networks.
    2. Right-click the network that you want to check settings for and select Properties.
    3. If you want to use this network for the cluster, make sure that the Allow the cluster to use this network option is selected. If you select this option and want the network to be used by clients (not just the nodes), make sure that the Allow clients to connect through this network option is selected.
    4. Please also run cluster validation wizard and see the Overall health of the Cluster.


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