In July 2024 ICANN agreed.internal as a reserved TLD which will never appear in the global root. This is a better match to the intent for the default value for cluster_domain_suffix than the current value .invalid, which was the only suitable choice at the time.
In July 2024 ICANN agreed
.internalas a reserved TLD which will never appear in the global root. This is a better match to the intent for the default value forcluster_domain_suffixthan the current value.invalid, which was the only suitable choice at the time.