In today’s article, I’m going to inform you about the Cisco IOS privileged EXEC mode command named “clear crypto isakmp.” This command is used by CCNAs (like you) to terminate active Internet Key Exchange (IKE) connections.

Below is the command’s syntax:

clear crypto isakmp [connection-id] [active | standby]

connection-id-The ID of the connection that needs to be cleared is contained in this optional argument. Default clearing of all connections will occur if this argument is not used with the command.

active-Only IKE security associations (SAs) that are currently in the active state can be cleared (removed) using this (optional) keyword.

standby – The only IKE SAs that can be cleared using this (optional) keyword are those that are in the standby (secondary) state. It’s important to keep in mind that when the router is in standby mode, it immediately resynchronizes the standby SAs, making it appear as though they weren’t cleared.

In the example below, all existing IKE connections are being cleared:

Router#clear crypto isakmp

Note: You can use the privileged EXEC mode command named “show crypto isakmp sa” to display (view) current IKE SAs.

Furthermore, if you choose to use the command, confirm that your router(s) are running Cisco IOS 12.3(11)T or higher.

I hope you found this article to be very informative and that it made it easy for you to understand how to use the clear crypto isakmp command. Visit my website if you want to learn more. There, you’ll find the most recent details on Cisco CCNA (640-553) Security exam strategies to help brighten your day.

To your success,