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No cdp run

As explained in Acing the CCNA Exam: Volume 2 Advanced Networking and Security

no cdp run is a Cisco IOS global configuration command that disables Cisco Discovery Protocol on the entire device.

Use no cdp run in global configuration mode to disable Cisco Discovery Protocol across the entire Cisco IOS device. This can reduce exposure of device information, such as software-version details that could support targeted attacks. section 1.1.3

Disable and verify global CDP

R1(config)# no cdp run R1(config)# do show cdp % CDP is not enabled The do show cdp command verifies that CDP is no longer running.

Distinguish global and interface-level behavior:

  • Use cdp run to reenable CDP globally. section 1.1.3
  • Use no cdp enable in interface configuration mode to stop one interface from sending or processing CDP advertisements. section 1.1.3
  • Global disablement overrides interface settings; CDP remains inactive on every interface until globally reenabled. section 1.1.3

How Acing the CCNA Exam: Volume 2 Advanced Networking and Security covers it

How deep it goes
Explains global configuration, verification, reenablement, and precedence over interface settings, but does not detail IOS internals.
Examples
Uses R1 CLI output showing no cdp run followed by do show cdp reporting that CDP is not enabled.
What you can do after
Apply it via Cisco IOS CLI and verify that CDP is no longer running on the device.
How it connects
Connects global CDP control with cdp run, no cdp enable, CDP verification commands, and LLDP as an alternative discovery protocol.
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Related concepts

This explainer was generated by Manning's knowledge graph from the text of Acing the CCNA Exam: Volume 2 Advanced Networking and Security. The section links point to the parts of the book it draws on.