Disable DTP on a Switch Port

D

DTP (Dynamic Trunking Protocol) is a Cisco proprietary protocol that is used to negotiate trunk links between two switches. By default, DTP is enabled on all switch ports, and it automatically tries to negotiate a trunk link with the other device connected to the port. In some cases, it may be necessary to disable DTP on a switch port, such as when connecting to a non- Cisco device or when security policies require that trunking be disabled.

To disable DTP on a switch port, you can use one of the following methods:

Option A: Configure the switch port as a trunk You can disable DTP on a switch port by configuring the port as a trunk link manually. To do this, you need to enter the following command in interface configuration mode:

Copy code
switchport mode trunk 

This command will configure the port as a trunk link, which will disable DTP negotiation on the port. The port will now be forced to operate as a trunk link, regardless of the type of device connected to it.

Option B: Add an interface on the switch to a channel group Another way to disable DTP on a switch port is to add the port to a channel group. When a port is added to a channel group, it automatically becomes a trunk link, and DTP negotiation is disabled. To add a port to a channel group, you need to enter the following command in interface configuration mode:

csharpCopy code
channel-group group-number mode on 

This command will add the port to the specified channel group and configure it as a trunk link. The port will now operate as a trunk link, regardless of the type of device connected to it.

Option C: Change the operational mode to static access You can also disable DTP on a switch port by changing the operational mode to static access. This mode disables DTP negotiation on the port and forces the port to operate as an access link. To change the operational mode to static access, you need to enter the following command in interface configuration mode:

Copy code
switchport mode access 

This command will change the operational mode of the port to static access and disable DTP negotiation. The port will now operate as an access link, regardless of the type of device connected to it.

Option D: Change the administrative mode to access Finally, you can disable DTP on a switch port by changing the administrative mode to access. This mode disables DTP negotiation on the port and forces the port to operate as an access link. To change the administrative mode to access, you need to enter the following command in interface configuration mode:

Copy code
switchport nonegotiate 

This command will change the administrative mode of the port to access and disable DTP negotiation. The port will now operate as an access link, regardless of the type of device connected to it.

In summary, there are several ways to disable DTP on a switch port, including configuring the port as a trunk link, adding the port to a channel group, changing the operational mode to static access, or changing the administrative mode to access.