CCNA 2.5.c: DTP – Dynamic Trunking Protocol (DTP)


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

Subscribe Now for access to the labs!




Leave a Reply
Built by TrailSix