CCNA 2.5.c: DTP – Dynamic Trunking Protocol (DTP)
Overview:
Dynamic Trunking Protocol is used to automatically negotiate the state of switchports
Study Notes:
DTP - Dynamic Trunking Protocol (DTP)
- Dynamic Trunking Protocol is how switchports automatically negotiate their mode before you ever configure them
- A switchport can be set to one of four modes - Dynamic Auto (default), Dynamic Desirable, Trunk or Access
- The chart below shows which mode a switchport will negotiate to (in white) given the starting mode of both switches (gray)
| Dynamic Auto | Dynamic Desirable | Trunk | Access | |
| Dynamic Auto | Access | Trunk | Trunk | Access |
| Dynamic Desirable | Trunk | Trunk | Trunk | Access |
| Trunk | Trunk | Trunk | Trunk | Limited Connectivity |
| Access | Access | Access | Limited Connectivity | Access |
- It's good to know how it works, but I recommend just turning it off completely to maintain more control over your switches and what is connecting to your network. By turning DTP off completely, you avoid switch spoofing and VLAN hopping.
PacketTracer Lab: CCNA-2.5.c-How-to-configure-Dynamic-Trunking-Protocol-DTP.pkt
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