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Cisco switches – Show cdp neighbors – Did you know…. Detail?

Craig Schellenberg

Oct 27 2022

3 min read

Three years ago I wrote a blog about how to find which port a device is plugged into on a Cisco switch if you knew the IP address of the device. In that blog is a command I’ve been using for decades: show cdp neighbors. It is almost always abbreviated to one of these:

show cdp nei
sho cdp nei
sh cd nei
sh cd n

Choose any variation of the abbreviations, they all work.

I’ve taken this command for granted through the years and only ever used it in that manner. I’ve been missing out on the additional syntax availability of “detail.”

How to Use the Show cdp neighbors detail Command

Here’s a Cisco switch environment that’s fairly typical after running the normal command. Of course you see the devices that are reporting CDP information to this switch like other Cisco switches, access points, etc. You are shown:

the local interface that the device is plugged into
the name of the device in the Device ID column
the type of device plugged in is shown in the Platform column
the interface on the attached device that is plugged into this switch in the Port ID column

How to Use cdp neighbors detail Command

However, let’s say I wanted to know more information about the device that is in Gi/1/0/51. For it type: show cdp nei gi/1/0/51 detail.

full details show about device

From here we have the switch name, its IP address for management, and the full type of switch. There is even the native vlan and code version of what it is running.

Why use the Show cdp neighbors detail Command?

In my last blog I stated that there was a need to know a little bit of the environment, and alluded to the network admin needing to know information about the switching infrastructure. Meaning, they would need to know the IP address of the switches inline. However, with this additional detail ability on the switch, it makes it that much easier to hunt down.

For this command, it isn’t necessary to specify the port you want more detail on. You can type simply show cdp nei detail to show all details for neighbors. It is a lot of information and might be useful when grabbing a copy of the config.

When grabbing information from a switch for backup configuration, I usually include a show cdp neighbors statement to grab the neighboring devices. I’ll likely update that going forward to have both the show cdp neighbors and show cdp neighbors detail commands when saving the configuration.

Have any questions about using the show cdp neighbors detail command to learn more information about devices plugged into a Cisco switch? Please feel free to reach out at any time!

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About the Author

Craig Schellenberg

Craig Schellenberg is a Senior Network Consultant at Sikich that works with businesses to improve their IT. Being detail oriented assists in his ability to design and deploy new solutions as well as troubleshoot complex issues. His primary areas of focus are virtualization and storage on premise (whether through VMware vSphere or Microsoft Hyper-V), Microsoft Cloud services such as Azure and Office 365, Microsoft SQL design and administration, backup/DR/Business Continuance, and network route/switch/firewalls. Craig holds many certifications including his MCSE (Microsoft Certified Solutions Expert) in Productivity, Messaging, and Cloud Platform and Infrastructure. Craig also holds multiple certifications of his VCP (VMware Certified Professional) including version 3, 4 (Data Center Virtualization), 5 (Data Center Virtualization), 5 (Desktop), Cloud, and 6 (Data Center Virtualization).