DTP

Question 1

When running “show int trunk”, what does the output “n-“ designate?

Answer 1

The encapsulation type (ISL or 802.1q) was auto-negotiated.

Question 2

What are the two DTP modes?

Answer 2

Auto and desirable.

Question 3

How do you turn off DTP?

Answer 3

Switchport mode trunk, switchport nonegotiate

Question 4

Briefly describe DTP.

Answer 4

Dynamic trunking protocol. Attempts to form trunks by sending a DTP frames out desirable ports.

Question 5

Is DTP industry standard?

Answer 5

No, it is Cisco proprietary.

Question 6

How often are DTP frames sent?

Answer 6

Every 30 seconds.

Question 7

DTP is a security risk because it allows the introduction of ___ into your network.

Answer 7

Rouge switches.

Question 8

What is a good command to use to check a trunk’s DTP status?

Answer 8

Show interface switchport. Look for the “Negotiation of Trunking” field. Use the pipe modifier.

Question 9

What is a good command to use to check a trunk’s DTP status?

Answer 9

Show interface switchport. Look for the “Negotiation of Trunking” field.

Question 10

If a switch supports ISL and 802.1q, what must you do before you can disable DTP?

Answer 10

Disable protocol negotiation, hard-code 802.1q protocol at the interface level.

Question 11

Define and Configure DTP

Answer 11

(config-if)switchport

Dynamic Trunking Protocol. Automatically choose port for Access or Trunk Mode.

Question 13

What order does DTP try to form?

Answer 13

1. Trunk ISL
2. Trunk 802.1q
3. Access

Question 14

How do you disable DTP?

Answer 14

switchport no negotiate

or

Question 15

what is errdisable dtp-flap?

Answer 15

change in trunk encap

Question 16

What does DTP do?

Answer 16

automatically negotiates a common trunk mode between switches

Question 17

How do you disable DTP when you configure both ends of the ISL manually?

Answer 17

switchport nonegotiate

Question 18

What are the 3 trunk encap modes?

Answer 18

isl, dot1q, negotiate (default

Question 19

What is DTP?

Answer 19

Dynamic Trunking Protocol - A Cisco-proprietary protocol used for negotiating trunking states. used to dynamically negotiate whether the devices on an Ethernet segment want to form a trunk and, if so, which type (ISL or 802.1Q).

Question 20

What are the 5 DTP modes?

Answer 20

-Access, member of a single VLAN.-Trunk, port attempts to negotiate trunking.-Non-negotiate, port set to trunk but does NOT negotiate.-Dynamic Desirable, Actively negotiates a trunk, and links if other side is Trunk, DD, or DA.-Dynamic Auto. Passively waits for other side to negotiate trunk. Links if other side is trunk or DD.

Question 21

How often are DTP frames sent out on switchports?

Answer 21

Every 30 Seconds.

Question 22

What does *DTP* stand for?

Answer 22

Dynamic Trunking Protocol

Question 23

What are the modes of DTP?

Answer 23

DTP has two modes, auto and desirable. Auto passively converts to a trunk if the neighbor sends a request. Desirable actively attempts to convert a link to trunk.

Question 24

What configuration command sets up DTP?

Answer 24

Switch(config-if)# switchport mode <auto></auto>

Question 25

What configuration command sets up non-DTP trunk?

Answer 25

Switch(config-if)# switchport mode trunk
Switch(config-if)# switchport no negotiate
Switch(config-if)# switchport trunk allowed vlan …