> # Checking for WWN Conflicts

> WWNs assigned to static iSCSI initiators by the system can be inadvertently returned to the system when an upgrade fails or you downgrade the system software (manually booting up an older Cisco MDS SAN-OS release without using the install all command). In these instances, the system can later assign those WWNs to other iSCSI initiators (dynamic or static) and cause conflicts.

> You can address this problem by checking for and removing any configured WWNs that belong to the system whenever such scenarios occur.

> ## Detailed Steps

> To permanently keep the automatically assigned nWWN mapping, follow these steps:

> 1. Choose End Devices > iSCSI in the Physical Attributes pane.

> You see the iSCSI tables in the Information pane.

> 2. Click the Initiators tab.

> You see the iSCSI initiators configured.

> 3. Check the Persistent Node WWN check box for the iSCSI initiators that you want to make static.
> 4. Click the Apply Changes icon to save these changes.

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