topic AAA New-Style to Legacy Mode in Network Access Control

AAA New-Style to Legacy Mode

Paul M Dycus — Fri, 27 Jun 2025 04:37:40 GMT

I have several switches in within my environment operating in new-style. Is there any way of reverting to legacy mode without factory defaulting the device?

Examples:

S1#authentication display config-mode
Current configuration mode is legacy

S2# authentication display config-mode
Current configuration mode is new-style

Re: AAA New-Style to Legacy Mode

Jens Albrecht — Fri, 27 Jun 2025 06:43:15 GMT

Hello @Paul M Dycus,

No, you cannot revert from "new-style" (IBNS 2.0) to "legacy" mode on Cisco switches without factory defaulting the device.

You need to backup the config, do a factory reset and then reconfigure them. Unfortunately there is no other way.

HTH!

Re: AAA New-Style to Legacy Mode

Jens Albrecht — Fri, 27 Jun 2025 07:05:51 GMT

Some additional note to make this clear:

If you switch from legacy to new-style you can revert back to legacy as long as you do not modify and save the config.

Please note that while you can revert to legacy style
configuration at any time unless you have explicitly
entered new-style configuration, the following caveats
should be carefully read and understood.

(1) If you save the config in this mode, it will be written
    to NVRAM in NEW-style config, and if you subsequently
    reload the router without reverting to legacy config and
    saving that, you will no longer be able to revert.

Source: Command Reference, Cisco IOS XE Amsterdam 17.2.x

Re: AAA New-Style to Legacy Mode

Karsten Iwen — Fri, 27 Jun 2025 07:32:06 GMT

What is the reason you want to go back? IBNS2 is tremendously more complex than IBNS1, but it is also the present and the future of access control on Cisco Switches. The best thing is to get used to it.

Re: AAA New-Style to Legacy Mode

MHM Cisco World — Fri, 27 Jun 2025 09:58:27 GMT

You can switch back to legacy mode by using the authentication display legacy command.

Try this command, if not work then sorry you need to factory reset.

MHM

Re: AAA New-Style to Legacy Mode

ahollifield — Fri, 27 Jun 2025 14:17:18 GMT

Why do you want to do this? IBNS 2.0 is FAR superior to IBNS 1.0

https://www.ise-support.com/cisco-ise-nad-configuration-templates/