CCNA 200-301 Training by CCNA Guru

List and briefly explain four common VLAN and trunk configuration errors:
■ Native VLAN mismatches: Trunk ports are configured with different native VLANs. This configuration error generates console notifications, causes control and management traffic to be misdirected, and poses a security risk.
■ Trunk mode mismatches: One trunk port is configured with trunk mode “off” and the other with trunk mode “on.” This configuration error causes the trunk link to stop working.
■ VLANs and IP subnets: User computers, for example, may have been configured with the incorrect IP addresses or subnet masks or default gateways. The result is loss of connectivity.
■ Allowed VLANs on trunks: The list of allowed VLANs on a trunk has not been updated with the current VLAN trunking requirements. In this situation, unexpected traffic or no traffic is being sent over the trunk.