...

Additional GCP-specific Information

IP Interface Netmask

By default, the netmask configured for an VM instance is /32 and Please note: The latest images provided by Stromasys use a /24 netmask for additional NICs. Therefore, the following information no longer applies to instances created with these images.

However, other base images used to create an instance, may use a netmask of /32 for additional NICs on the VM instance. This means that only ARP requests for the default gateway are answered by the Google metadata server. When In such cases, when providing a dedicated NIC to the Solaris guest system, that is, the internal IP address of the interface is not configured on the Linux level, but on the Solaris level, please note the following points:

• The netmask on Solaris has to be set to a value that includes the default gateway (e.g., /24). Otherwise, Solaris will return an error when setting the default gateway (network unreachable).
• If Solaris should communicate with systems on the same subnet, it currently needs a static ARP entry for these systems (arp -s <target-ip> <target-mac>). This is because the ARP requests sent by Solaris for the MAC addresses of these systems will not be answered by the Google metadata server and they will not be forwarded to the target system.

...