> # About Auto-Learning

> You can instruct the switch to automatically learn (auto-learn) the port security configurations over a specified period. This feature allows any switch in the Cisco MDS 9000 Family to automatically learn about devices and switches that connect to it. Use this feature when you activate the port security feature for the first time as it saves tedious manual configuration for each port. You must configure auto-learning on a per-VSAN basis. If enabled, devices and switches that are allowed to connect to the switch are automatically learned, even if you have not configured any port access.

> When auto-learning is enabled, learning happens only for the devices or interfaces that were not already logged into the switch. Learned entries on a port are cleaned up after you shut down that port if auto-learning is still enabled.

> Learning does not override the existing configured port security policies. So, for example, if an interface is configured to allow a specific pWWN, then auto-learning will not add a new entry to allow any other pWWN on that interface. All other pWWNs will be blocked even in auto-learning mode.

> No entries are learned for a port in the shutdown state.

> When you activate the port security feature, auto-learning is also automatically enabled.

> Note If you enable auto-learning before activating port security, you cannot activate until auto-learning is disabled.

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