Errdisable Concept

The errDisable status is the  feature utilized by Cisco Catalyst switches that is designed to protect the network from issues resulting from switch misconfiguration and other errors in our network.

The errDisable status describes a port that has been shut down by the switch operating system due to an error being detected on the port. Once a port is placed into the errDisable state, an administrator must manually re-enable the port.
This feature is reserved for errors that might seriously jeopardize the stability of the switch or the entire LAN network.

 You, as an adminsitrator,  can also configure Cisco Catalyst switches to automatically enable errDisabled ports after a configurable timer expires

Let's see them in action

Troubleshooting Steps

As with any problem that you might try to solve, you should take clear troubleshooting steps, depending on the issue you are trying to tackle. The following describes each of the troubleshooting steps you should take when trying to determine the cause of the errDisable state of a port:

1. Determine an issue exists
2. Determine why the port(s) were disabled
3. Resolve the issue(s)
4. Re-enable the port(s)

 So let's do an exercise :The first part in green we are doing a port-security configuration, the second part in yellow we are applying an errdisable recovery interval .I will set it to 30 seconds for our lab  ( the default is 300 seconds)

Now let see what happens when we connect a cable from your computer to that port

Beisdes that three things happens:

• Port LED changes color from green to orange
• Loss of functionality in the network
• Notification via network management systems

...and 30 seconds later , the port begin to come out of that err-disable state..:

Them, you should go to fa0/41 , disconnect the cable and disable port security so it wouldn't be bouncing from errdisable state forever  (in green the commands , in yellow the results)!

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This lab was successful ! Thanks for watching and please share!