We have a three node active / active / passive Windows 2012 cluster. 

One node contains a single instance (Role) of SQL Server, a second node contains two instances (Roles) of SQL Server.  One of the instances is not being used yet.  

I took the unused role off-line and in the process, the primary network took all three of the public IP addresses off-line.  

If we take one role off-line, why would the other IP addresses also go off-line??

It apparently is a configuration issue but I cannot find any type of documentation in this. 

There is lots of information on line about configuring SQL Server within a cluster.  Until Hyper-V came out, I would have ranked SQL as the application most likely to be clustered.

You are right, it is most likely a configuration issue, but you did not provide any information about how you configured, so we need to guess.  Could you provide some information about all networks on the cluster?  What sort of storage is in use?  When you say public IP addresses, are you referring to the IP addresses that you assigned to the individual SQL instances during installation, or to the IP addresses of the physical hosts and the cluster IP address? 

Hi Progeek11,

Would you pass the storage validation before you create the cluster?  Please run the cluster validation it will quickly locate the common potential issue.

More information:

Use Validation Tests for Troubleshooting a Failover Cluster

https://technet.microsoft.com/en-us/library/Cc770807.aspx

Best Regards,