I inherited a network and see some odd configurations that I don't normally do and can't think of a reason for it. One of them has the following statements
no spanning-tree vlan 20
no spanning-tree vlan 27
no spanning-tree vlan 90
Is there a reason anyone could think of for this?
in this case I strongly recommend to enable STP on all Vlans in use even if they are at the moment confined in a single switch.
I agree that this configuration is not logical and unsafe.
Hope to help