> # Port Security Activation

> By default, the port security feature is not activated in any switch in the Cisco MDS 9000 Family.

> By activating the port security feature, the following apply:

> - Auto-learning is also automatically enabled, which means:
> - From this point, auto-learning happens only for the devices or interfaces that were not logged into the switch.
> - You cannot activate the database until you disable auto-learning.
> - All the devices that are already logged in are learned and are added to the active database.
> - All entries in the configured database are copied to the active database.

> After the database is activated, subsequent device login is subject to the activated port bound WWN pairs, excluding the auto-learned entries. You must disable auto-learning before the auto-learned entries become activated.

> When you activate the port security feature, auto-learning is also automatically enabled. You can choose to activate the port security feature and disable auto-learning.

> Tip If a port is shut down because of a denied login attempt, and you subsequently configure the database to allow that login, the port does not come up automatically. You must explicitly issue a no shutdown CLI command to bring that port back online.

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