What Does DTP Mean in 200-301? — Definition & Guide

Full Definition

DTP is a Cisco proprietary protocol that allows switches to negotiate whether to form a trunk link. DTP modes include: Dynamic Auto (waits for the other side to initiate), Dynamic Desirable (actively tries to form a trunk), Trunk (forces trunk mode), and Access (forces access mode). The combination of modes on each end determines whether a trunk forms. DTP is enabled by default on most Cisco switch ports.

CLI Command

switchport mode dynamic desirable   ! actively negotiates trunk
switchport mode dynamic auto       ! passively waits
switchport nonegotiate             ! disables DTP

Exam Trap — Don't Get Fooled

Best practice is to disable DTP on access ports ('switchport mode access') and on trunk ports ('switchport nonegotiate'). Leaving DTP enabled allows an attacker to negotiate a trunk and send tagged frames — a VLAN hopping attack.

Related 200-301 Terms

VLAN

A logical segmentation of a switch network into separate broadcast domains.

Trunk Port

A switch port configured to carry traffic for multiple VLANs using 802.1Q tags.

Native VLAN

The VLAN whose frames pass untagged on a trunk link — VLAN 1 by default.

Frequently Asked Questions

What does DTP mean on the 200-301 exam?

DTP is a Cisco proprietary protocol that allows switches to negotiate whether to form a trunk link. DTP modes include: Dynamic Auto (waits for the other side to initiate), Dynamic Desirable (actively tries to form a trunk), Trunk (forces trunk mode), and Access (forces access mode). The combination of modes on each end determines whether a trunk forms. DTP is enabled by default on most Cisco switch ports.

How does DTP appear as a trap on the 200-301?

Best practice is to disable DTP on access ports ('switchport mode access') and on trunk ports ('switchport nonegotiate'). Leaving DTP enabled allows an attacker to negotiate a trunk and send tagged frames — a VLAN hopping attack.

How important is DTP on the 200-301 exam?

DTP falls under the VLANs domain of the 200-301 exam. Understanding it in context with related terms like vlan and trunk-port is essential for answering scenario-based questions correctly.