DTP (Dynamic Trunking Protocol): How It Works and Why You Should Disable It
DTP lets switches negotiate trunk formation automatically—but this convenience comes with security risks that make disabling it a best practice in production networks.
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VLAN Access Ports and Switchport Modes: Access, Trunk, and Dynamic
Learn the differences between access mode, trunk mode, and dynamic trunking protocol negotiation on Cisco Catalyst switches, and why static configuration is the production standard.
VTP Configuration on Cisco Switches: Versions 1, 2, and 3
VTP automates VLAN propagation across switches—but a single switch with a high revision number can wipe all VLANs from your network. Learn how to configure VTPv3, manage revision numbers, and avoid the most dangerous VLAN mistake.
VLAN Trunking Explained: 802.1Q, Allowed Lists, and Trunk Negotiation
Learn why VLAN trunks exist, how 802.1Q tagging works, the difference between ISL and 802.1Q, and how allowed VLAN lists and trunk negotiation function in Cisco networks.