> # Enabling the Persistent FC ID Feature

> If you connect to the switch from an AIX or HP-UX host, be sure to enable the persistent FC ID feature in the VSAN that connects these hosts.

> A persistent FC ID assigned to an F port can be moved across interfaces and can continue to maintain the same persistent FC ID.

> ## Restrictions

> - FC IDs are enabled by default. This change of default behavior from releases prior to Cisco MDS SAN-OS Release 2.0(1b) prevents FC IDs from being changed after a reboot. You can disable this option for each VSAN.
> - Persistent FC IDs with loop-attached devices (FL ports) need to remain connected to the same port in which they were configured.
> - Due to differences in Arbitrated Loop Physical Address (ALPA) support on devices, FC ID persistency for loop-attached devices is not guaranteed.

> ## Detailed Steps

> To enable the persistent FC ID feature, follow these steps:

> 1. Expand Fabric > All VSANs and then select Domain Manager in the Logical Domains pane for the fabric and VSAN that you want to enable the Persistent FC ID feature for.

> You see the running configuration of the domain in the Information pane.

> 2. Select the Persistent Setup tab and check the enable check box for each switch in the fabric that will have persistent FC ID enabled.
> 3. Click the Apply Changes icon to save these changes.

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