Cisco Discovery Protocol

Router#show cdp

Displays global CDP information (such as timers)

Router#show cdp neighbors

Displays information about neighbors

Router#show cdp neighbors detail

Displays more detail about neighbor device

Router#show cdp entry word

Displays information about device named word

Router#show cdp entry *

Displays information about all devices

Router#show cdp interface

Displays info about interfaces that have CDP running

Router#show cdp interface x

Displays info about specific interface x running CDP

Router#show cdp traffic

Displays traffic infopackets in/out/version

Router(config)#cdp holdtime x

Changes length of time to keep CDP packets

Router(config)#cdp timer x

Changes how often CDP updates are sent

Router(config)#cdp run

Enables CDP globally (on by default)

Router(config)#no cdp run

Turns off CDP globally

Router(config-if)#cdp enable

Enables CDP on a specific interface

Router(config-if)#no cdp enable

Turns off CDP on a specific interface

Router#clear cdp counters

Resets traffic counters to 0

Router#clear cdp table

Deletes the CDP table

Router#debug cdp adjacency

Monitors CDP neighbor information

Router#debug cdp events

Monitors all CDP events

Router#debug cdp ip

Monitors CDP events specifically for IP

Router#debug cdp packets

Monitors CDP packet-related information


Although CDP is an excellent source of information to you the network administrator, is it a potential security risk if a hacker gains access to one of your systems. The information that you gain through CDP is also gained by the hacker.

After you have used CDP to gather your information in a production environment, turn it off to thwart any bad people from using it for no good.

CCNA Self-Study(c) CCNA Portable Command Guide
CCNA Portable Command Guide
ISBN: 1587201585
EAN: 2147483647
Year: 2006
Pages: 261
Authors: Scott Empson

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