Radius Inaccessible Authentication Bypass

gilou_1973 · ‎09-23-2009

Hello,

I'd like to know if it's possible to implement a such mechanism on a Cisco 2950 platform.

I'd like to avoid that my clients ports are unauthorized in case of a failure of my radius servers. Is there a way to implement it on a 2950G.

Richard Burts · ‎09-24-2009

gildas

Would I be correct to assume that you have your 2950G configured with a backup authentication method if the Radius server is not available and that your issue is what to do about authorization?

I have not done this on a 2950G and can not know that it works, but this solution generally works in IOS and I assume that it will work on your 2950G:

aaa authorization exec default group radius if-authenticated

Give it a try and let us know if it works.

HTH

Rick

HTH

Rick

gilou_1973 · ‎09-28-2009

Hi Rick,

Thanks for your answer but what I mean is the following.

I've implemented the dot1x port control on my switchs and I'd like to bypass this security if my radius server is considered down or unreachable by the authenticator.

I know that it's possible on a catalyst 4500 and is known as "Configuring a port as a critical port in order to enable the Inaccessible Authentication Bypass feature".

I hope that my explanation is clearer and that I don't mistake

Thanks

sdfgdfgfddfdfgdf · ‎02-12-2019

Old thread I know, but I have the same issue currently:

There doesn't appear to be any kind of option like critical ports, or , or a workaround.

I have tried setting the fail and guest vlans on the ports, but these only work when the radius server is accessible.

Without the radius server being alive, no ports can be authenticated or failed open.

Greatful if anyone know of a way to deal with this, or if there is another command I am unaware of.

Rob Ingram · ‎02-12-2019

Hi,

These commands entered under the interface should authorize the connection in the event the RADIUS server is down/dead:-

Switch(config-if)# authentication event server dead action reinitialize vlan 20

Switch(config-if)# authentication event server dead action authorize voice

Reference here.

HTH

sdfgdfgfddfdfgdf · ‎02-13-2019

Hi and thanks for taking the time to look at this and respond.

Unfortunately, that reference is for ios 15, and those commands are not available in ios 12.1(22)EA13

The catalyst 2950 is not supported above 12.1

I don't know if there is anything helpful in 12.1(22)EA14, but as it's an EOL switch I sadly can't find a download.

hslai · ‎02-16-2019

IEEE 802.1x inaccessible authentication bypass appears needing a minimal IOS release of 12.2(25)SED or 12.2(25)SEE, per Release Notes for the Catalyst 3750, 3560, 2960-S, and 2960 Switches, Cisco IOS Release 12.2(58)SE1 and Later