In this video, we take a look at how EEM scripts can be utilized alongside Low Impact mode to enable ports to fail open.
Below are EEM Scripts that can be reused and modified for your environment.
Note: For single RADIUS Servers use the “%RADIUS-4-RADIUS_DEAD” syslog pattern and for a group of RADIUS servers use the “%RADIUS-3- ALLDEADSERVER” syslog pattern.
If your devices utilize command authorization then you need to ensure that the script can still run in the event of a failure. Enter the following command at the end of each applet to ensure command authorization is bypassed.
In this article we are going to take a look at how to capture Extensible Authentication Protocol Over LAN (EAPOL) and Remote Authentication Dial-In User Service (RADIUS) packets using Wireshark. This article can be useful for troubleshooting 802.1x within your environment and can also be used for learning purposes. The following topology has been used to gather the required output for this article. Note: This article will only cover the switch configurations that are required to gather EAPOL and RADIUS configuration. Overview of the Topology The supplicant is configured to perform 802.1x using EAP-TLS as the authentication method The user certificate on the supplicant will be used for authentication The supplicant has Wireshark installed Cisco ISE is used for authentication and authorisation The supplicant is assigned to VLAN 10 upon authentication and all other endpoint ports are assigned to VLAN 99 Sniffer device is running Wireshark in order to capture RADIUS flows via SPAN 802.1x ...
In this article I would like to go through a typical Identity Based Networking Services (IBNS 2.0) configuration, breaking down each so that we can better understand the configuration. While there are many configuration elements of secure network access, this article will focus on the Cisco Common Classification Policy Language (C3PL) configurations. I must admit, when I first got a glance of some IBNS 2.0 configuration, I was a little taken back at the amount of configuration. However, after reading up about it, and refreshing parts of my CCNP R&S skills, I was able to understand how IBNS 2.0 configuration comes together. This article will NOT focus on use cases for using IBNS 2.0, however, I would like to point out some good, online documentation that will provide you with some useful information. IBNS 2.0 at a glance Identity Based Networking Command Reference Guide Cisco Live IBNS 2.0 Lab Guide Configuring Identity Service Templates Configuring IEEE 802.1x Port-Based Authent...
As part of my on-going studying for the CCNA Security 210 – 260 certification I have been exploring different types of network attacks, one of which is CAM table overflow attacks. In this article I would like to share what I have learnt and provide a demonstration of the attack carried out in a lab environment. To understand my demonstration, you first need to understand how a CAM table overflow attack works and what happens as a result of the attack. Switches build Content Addressable Memory (CAM) tables based on mac-addresses and port numbers. When a switch receives a frame it checks the table to see if the source mac-address is already known, if the source mac-address is unknown the switch will add the mac-address to the table along with the port number. The switch then checks the destination layer two frame and if no entry exists the switch broadcasts the frame out of all ports except the port in which the frame was received. Presuming the destination mac-address wants to res...
Throughout my time working with Cisco ISE, I’ve come across a few different errors when configuring ISE to perform Certificate Revocation Lists (CRL) lookups using Microsoft’s Public Key Infrastructure (PKI). In this article I would like to show you how we can avoid CRL download issues that could ultimately stop an endpoint from authenticating onto a network when configured for Network Authentication Control (NAC). CRL checking is useful for checking of expired certificates and when an environment has Cisco Identity Services Engine deployed for secure network access, this can be useful for ensuring revoked digital certificates are not reused when they’ve been revoked. CRL lookups can be costly to your network because of the lookups that are performed and Online Certificate Status Protocol (OCSP) can be used as a more efficient way to check revoked certificates. However for the purpose of this article we will focus only on Certificate Revocation Lists. In this article I will demonstrate...
In this article I would like to cover how to configure SNMPv3 for Cisco Identity Services Engine (ISE). In a few deployments I’ve done, I’ve come across the need to configure ISE to send SNMPv3 traps to a Network Management System (NMS). SNMPv3 is perfect for ensuring the authentication and encryption of SNMP traffic, something that can’t be done with inferior SNMP versions. Now, one would assume that we could just go ahead and configure ISE for SNMP via the GUI however, unfortunately that’s not the case. To actually configure ISE to send traps to an NMS system we need to configure the settings via the CLI. The demonstration in the article is performed using a standalone ISE. This demonstration also assumes that you have connectivity between your NMS platform and ISE. To see a live demonstration with testing, refer to the video that accompanies this article. Configuration Steps Enable SNMP So that we can configure the required SNMPv3 settings for ISE, SNMP needs to be enabled. iselab/a...
