The number of IP addresses you need depends on what you want to do and how your environment is built and what IP protocols you are using. The number of addresses you need will be the same regardless of if your cluster is Active/Active or Active/Passive.

For W2012 and above each node in the cluster will normally have an IPv4 and an IPv6 address unless you have specifically disabled IPv6. Most places that only assign IPv4 addresses will let DHCP assign the IPv6 address so you do not have to assign these yourself.

You also need to think about port numbers, particularly if you plan to use Kerberos (you should be planning to use Kerberos!). If you have both a default and named instance clusters for the SQL DB engine then each instance needs its own port. This is because you need a port-specific SPN for each instance to allow Kerberos authentication.

You may need some or all out of the list below. If your site standard is to publish both IPv4 and IPv6 addresses then you need 1 address for each protocol.

For each cluster node:

1 address for each cluster node for client traffic

1 address for each cluster node for data traffic (depending on how your storage is configured)

If you need multiple NICs to get the required throughput then consider teaming the NICs (1 client team, 1 storage team) rather than using a dedicated IP address for each NIC.

Some sites will split high-priority and low-priority data traffic into separate NIC teams each with their own IP address. This allows backups to write to disk without impacting IO for your critical DBs.

For the Windows cluster:

1 address for client traffic

1 address for cluster handshake traffic

For SQL Server:

1 address for each SQL DB engine cluster

1 address for each MSDTC cluster (MSDTC can be added as a service within the DB engine cluster and share the IP, or set up as its own cluster with its own IP)

1 address for each Availability Group listener

1 address for each Analysis Services cluster

Other components:

1 address for SSRS cluster if you decide to cluster SSRS

1 address for each Master Data Services cluster if you decide to cluster MDS

If you use SQL FineBuild to install your clusters, by default it will take the Windows Cluster IP and find the next highest unused IP address for each of the SQL Server, MSDTC and SSRS clusters. However if you need to use specific IP addresses with FineBuild these can be supplied as parameters.