Keeping a Layer 3 vlan up when nothing is connected

[paragonbank]

I'm guessing this has been asked a 100 times but here my scenario....

I have a number of layer 3 vlan's on a switch, as the switch is controlled by Cisco ISE a connected device could exist in 3 different vlan's dependant on its status (powered up, logged on or needs remediation)..... 

From time to time a certain vlan may not have a device connect (i.e. no PC's need remediating), therefore that vlan will go down....

This isn't the issue.... The issue to our Cyber security team and our Tenable scanning server. This is configured to scan all know networks... If the remediation vlan is down because no PC's need remediating then all scanning traffic follows the default route to our FTD which is the main gateway.....

Any ideas how I can keep the vlan up????

Thanks

[MHM Cisco World]

Allow in trunk I think do job.

[Martin L]

are we talking about SVI, like interface vlan x ?  there is command that you can put under at least 1 access vlan x port Or trunk port to prevent SVI to go down. I think is switchport autostate  (use ? to find particular command for your ios )

also, keep vlan on trunks (at least 1 trunk) and in database, as suggested by MHM

Regards, ML
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