What is the default native VLAN on all trunk ports?

The default native VLAN on all trunk ports in a Cisco switch is VLAN 1. When a trunk link is established, it allows multiple VLANs to traverse a single network link. The native VLAN is used to handle untagged traffic on this trunk link, which is significant because devices connecting over a trunk might not always support VLAN tagging.

VLAN 1 is the default configuration for the native VLAN in Cisco switches. This means if no modifications are made, any untagged frames received on a trunk port will be associated with VLAN 1. Understanding the implications of using the default VLAN is crucial for network security and proper VLAN configuration since VLAN 1 is often targeted by attackers due to its default nature. It is generally recommended to avoid using VLAN 1 for user data traffic to improve security.

The other VLAN numbers listed, such as 1005, 4094, and 4095, do not serve as the default native VLAN for trunk ports in standard Cisco configurations. VLAN 1005 is an example of a user-defined VLAN, while 4095 is reserved for special purposes like management or broadcast traffic, and 4094 is the maximum usable VLAN ID in most configurations, but none are set as defaults for native VLAN purposes