Number of configurable DDNS entries
Starting in FortiOS 7.4.0, the number of DDNS entries that can be configured is restricted by table size. The limits are 16, 32, and 64 entries for entry-level, mid-range, and high-end FortiGate models respectively.
After upgrading to FortiOS 7.4.0 or later, any already configured DDNS entries that exceed the limit for the FortiGate model in use will be deleted. For example, if a user has 20 DDNS entries before upgrading to 7.4.0 and is using a entry-level FortiGate model, the last four DDNS entries will be deleted after upgrading.
In such instances where the number of DDNS entries exceeds the supported limit for the FortiGate model in use, users have the option to upgrade their FortiGate model to one that supports a higher number of DDNS entries.