
Unless the operation of [DTP](/dtp) is completely [disabled](/dtp-how-to-disable), or a switchport is configured as an [access port](/switchport-access), a switchport configured in trunk mode will always send out DTP messages regardless of the [mode](/switchport-modes) it has been configured with.

For example, even though the switchport mode dynamic auto is passive in terms of initiating a [trunk](/switchport-trunk) negotiation, it still sends out DTP frames.  

## Links

https://forum.networklessons.com/t/cisco-dtp-dynamic-trunking-protocol-negotiation/1083/34?u=lagapidis

https://networklessons.com/switching/cisco-dtp-dynamic-trunking-protocol-negotiation/

DTP - Sending of Frames

DHCP excluding address on a Cisco IOS DHCP server

DHCP multiple IP helper-addresses

DHCP multiple servers on the same subnet

DHCP offer message sent as broadcast

DHCP option 82

DHCP relay agent

DHCP relay support for MPLS VPN

DHCP renewal rebinding

DHCP snooping rate limiting best practice

DHCP trusted and untrusted ports

DHCP

DHCPv6 - Modes of Operation

DHCPv6 - determining the IPv6 prefix assigned to an interface

DHCPv6 lease times on a Cisco IOS device

DHCPv6 relay agent

DMVPN - Dual-Hub Single-Cloud with redundant spoke links config guidelines

DMVPN - IPsec encryption order of operations

DMVPN - NHRP purge request

DMVPN - NHRP session attributes

DMVPN - OSPF and multiple areas

DMVPN - Phase 2 BGP peerings

DMVPN - Phase 2 EIGRP neighbor adjacencies

DMVPN - Phase 2 OSPF neighbor adjacencies

DMVPN - Phase 2 and multicast traffic

DMVPN - Phase 2 and summarization

DMVPN - Using the GRE tunnel key

DMVPN - What is the best routing protocol to use

DMVPN - mappings on hub and spokes

DMVPN - multicast commands

DMVPN - nhrp map and nhs command syntax

DMVPN - spoke redundancy

DMVPN - using a default route

DMVPN State of a tunnel

DMVPN dual hub dual cloud

DMVPN dual hub single cloud

DMVPN hierarchical topology

DMVPN redundancy options

DMVPN with more than two hubs

DMVPN

DNS - Authoritative Flag

DNS - Authoritative Server

DNS - Caching

DNS - Recursive Resolver

DNS - What is a delegation zone

DNS - stub zone

DNS - understanding zones

DNS cache windows PC

DSL - Asymmetric Digital Subscriber Line (ADSL)

DTP - best practice to disable

DTP - how to disable

Debug Condition Command Restrictions in Cisco IOS

Decrypt IPSec ESP traffic with Wireshark

Demand Circuits

Demarcation point

Determining an SSM multicast group

Difference between per-prefix LFA and per-link based LFA

Differences between CCIE and CCDE lab exams

Diffserv recommended configuration

Distribute-lists - using route maps to set attributes

Distribute-lists and named extended ACLs

ECMP Multicast Routing Cisco Nexus Switches

EEM - action mail

EEM - exit status variable

EEM Cisco Embedded Event Manager

EEM Matching a string within CLI output

EEM sync and skip keywords

EIGRP - Advertised metric is cumulative

EIGRP - Advertising a route using the network command

EIGRP - DUAL Algorithm and FD Set to Infinity

EIGRP - External routes from different ASes

EIGRP - Feasible Successors and the DUAL Algorithm

EIGRP - Hello interval and Hold time

EIGRP - Hop Count

EIGRP - Message TTL value of 2

EIGRP - Metric Equation Multipliers

EIGRP - Network command syntax

EIGRP - Queries

EIGRP - RTP's reliable message exchange process

EIGRP - Reliable Multicast

EIGRP - Router ID and loop prevention

EIGRP - SIA Process and RTP retry attempts

EIGRP - Source of values for metric calculation

EIGRP - Static neighbors over any L2 technology

EIGRP - Stub Router

EIGRP - Stub default behavior

EIGRP - Stub router types

EIGRP - Summarization per interface

EIGRP - Understanding Advertised Distance (AD)

EIGRP - Update message exchange process

EIGRP - Viewing RTP in Wireshark

EIGRP - af-interface configuration mode

EIGRP - how metrics are sent in updates

EIGRP - internal vs external routes

EIGRP - metric computation method

EIGRP - metric equation

EIGRP - named mode name