📖 What is DTP (Dynamic Trunking Protocol)?
A Cisco-proprietary protocol used to automatically negotiate trunking between two switches.
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Sensei Says:
"For security reasons, best practice is to manually configure links as trunks ('switchport mode trunk') or access ('switchport mode access') and disable DTP using 'switchport nonegotiate'."
📚 Certification: Certified Network Associate (200-301)
🔑 What are the Key Concepts of DTP (Dynamic Trunking Protocol)?
- ▸ Cisco-proprietary negotiation of trunking status
- ▸ Security vulnerability related to VLAN hopping if left enabled on edge ports
- ▸ Modes of operation: dynamic auto and dynamic desirable
🎯 How does DTP (Dynamic Trunking Protocol) appear on the 200-301 Exam?
Disabling DTP on an interface connected to a host device for security.
Predicting the resulting link state when two different DTP modes are connected.
❓ Frequently Asked Questions
How do you completely disable DTP on an interface?
Configure the port statically (e.g., 'switchport mode access') and then apply the 'switchport nonegotiate' command.
Will a trunk form if a Cisco switch using DTP connects to a non-Cisco switch?
No, because DTP is Cisco-proprietary. The link must be manually configured as a trunk on both sides.
Related Terms from Certified Network Associate
Default VLAN (VLAN 1)
Fully Specified Static Route
Dynamic Host Configuration Protocol (DHCP)
Northbound API
Unshielded Twisted Pair (UTP)
EtherChannel