Unassigned Cisco switch ports remain in which VLAN?

Unassigned Cisco switch ports remain in VLAN 1 by default. This VLAN serves as the default VLAN on Cisco switches and is typically used for management purposes and for the handling of untagged traffic.

When a port is configured but not assigned to a specific VLAN, it will automatically belong to VLAN 1, which means that any devices connected to that port will communicate over this VLAN unless they are explicitly configured to be part of another VLAN. This behavior is integral for network administrators, as it provides a level of predictability in how unassigned ports will operate.

In general, it is good practice to change the default VLAN for security reasons, as maintaining devices on VLAN 1 can expose them to unnecessary risk. However, the default behavior of unassigned ports connecting to VLAN 1 remains a fundamental aspect of Cisco switch operation.