You do not need to configure a private network for a single-node cluster.
Sun Cluster software uses the private network for internal communication between nodes. A Sun Cluster configuration requires at least two connections to the cluster interconnect on the private network. You specify the private-network address and netmask when you configure Sun Cluster software on the first node of the cluster. You can either accept the default private-network address (172.16.0.0) and netmask (255.255.0.0) or type different choices if the default network address is already in use elsewhere in the enterprise.
After the installation utility (scinstall, SunPlex Manager, or JumpStart) has finished processing and the cluster is established, you cannot change the private-network address and netmask. You must uninstall and reinstall the cluster software to use a different private-network address or netmask.
If you specify a private-network address other than the default, the address must meet the following requirements:
Use zeroes for the last two octets of the address.
Follow the guidelines in RFC 1597 for network address assignments.
You can contact the InterNIC to obtain copies of RFCs. See “Planning Your TCP/IP Network” in System Administration Guide, Volume 3 (Solaris 8) or “Planning Your TCP/IP Network (Task)” in System Administration Guide: IP Services (Solaris 9) for instructions.
If you specify a netmask other than the default, the netmask must minimally mask all bits that are given in the private-network address.