IPv4 and IPv6 address prioritization for licensing communication.

Yes

Question:

How to dictate licensing communication to be prioritize on IPv4 or IPV6 addresses (to be used for communication with client) or use only one of them?

Answer:

FNP_IP_ENV:

This client-side environment variable determines how the client's IP address is presented to the server.
• If the variable is set to a value of 0, 4, or 6, the IP address sent to the server is resolved on the client, from the client's hostname, as follows:
• If the variable is set to 0, then the client resolves its hostname to both an IPv4 and an IPv6 address.
• If the variable is set to 4, then the client resolves its hostname only to an IPv4 address.
• If the variable is set to 6, then the client resolves its hostname only to an IPv6 address.

• If the variable is set to 1 (default value), the client-side hostname resolution is bypassed. Instead, the client's IP address is determined from the socket connection at the server, which means that a NAT-translated IP address for the client can be obtained.

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FNP_IP_PRIORITY:

The environment variable FNP_IP_PRIORITY decides the IP priority for hostname resolution, and can apply to the server, the client, or utilities like lmhostid. Values are:

• 4 (default): hostname resolution is attempted to IPv4 address first; if that fails, resolution to IPv6 address is attempted.
• 6: hostname resolution is attempted to IPv6 address first; if that fails, resolution to IPv4 address is attempted.

Examples of when to set to this value:
• on the machine where running lmhostid, if IPv6 address is required from lmhostid ‐internet
• on the client if node-locked IPv6 INTERNET HostID is used
• on the server if IPv6 address is used in the options file or as a server HostID.
Note: IPv4 and IPv6 addresses cannot be mixed on the server.

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Clients send both IPv4 and IPv6 addresses in the checkout message to the server.
In some licensing models, it may be desirable for the server to operate on a NAT-translated IP address instead of the client's actual IP address—for example, if using the EXCLUDE keyword in an options file to exclude all clients originating from behind a specific firewall. To enable such use cases, set FNP_IP_ENV=1 on the client. Setting this environment variable prevents the client resolving its own hostname to an IP address, which means the server instead obtains an IP address for the client from the socket connection.