Enterasys Networks 9034385 - Manual (Page 42)

Scenario 1: Intelligent Wired Access Edge
3-4 Use Scenarios
Scenario 1 Implementation
In the intelligent wired edge use scenario, the five NAC functions are implemented in the
following manner:
1. Detection ‐ The userʹs end‐system connects to the network. The edge switch sends a RADIUS
authentication request (802.1X, web‐based, or MAC authentication) with the associated
credentials to the NAC Gateway.
2. Authentication ‐ If the end‐system is authenticating to the network using 802.1X or web‐based
authentication, the NAC Gateway proxies the RADIUS authentication request to a backend
authentication (RADIUS) server to validate the identity of the end user/device. For end‐systems
that are MAC authenticating to the network, the NAC Gateway can be configured to either proxy
the MAC authentication requests to the RADIUS server or locally authorize MAC authentication
requests. If only MAC authentication is deployed on the network, and the NAC Gateway is
configured to locally authorize MAC authentication requests, a backend RADIUS server is not
required for the Enterasys NAC solution.
3. Assessment ‐ After the identity of the end‐system or end user is validated via authentication,
the NAC Gateway requests an assessment of the end‐system according to predefined security
policy parameters. The assessment can be agent‐based or agent‐less, and is executed locally by the
NAC Gatewayʹs assessment functionality and/or remotely by a pool of assessment servers.
4. Authorization ‐ Once authentication and assessment are complete, the NAC Gateway allocates
the appropriate network resources to the end‐system based on authentication and/or assessment
results. For Enterasys policy‐enabled edge switches, the NAC Gateway formats information in the
RADIUS authentication messages that directs the edge switch to dynamically assign a particular
policy to the connecting end‐system. For RFC 3580‐capable edge switches, the NAC Gateway
formats information in the RADIUS authentication messages (in the form of RFC 3580 VLAN
Tunnel attributes) that directs the edge switch to dynamically assign a particular VLAN to the
connecting end‐system. If authentication fails and/or the assessment results indicate a
noncompliant end‐system, the NAC Gateway can either deny the end‐system access to the
network by sending a RADIUS access reject message to the edge switch, or quarantine the end‐
system by assigning a Quarantine policy or VLAN to the end‐system on the edge switch.
5. Remediation ‐ When the quarantined end user opens a web browser to any web site, its traffic is
dynamically redirected to a Remediation web page that describes the compliance violations and
provides remediations steps for the user to execute in order to achieve compliance. After taking
the appropriate remediation steps, the end user clicks on a button on the web page to reattempt
network access, forcing the re‐assessment of the end‐system. At this point, the Enterasys NAC
solution transitions the end‐system through the entire NAC cycle of detection, authentication,
assessment, and authorization, re‐assessing the security posture of the end‐system to determine if
the remediation steps were successfully followed. If the end‐system is now compliant with
network security policy, the NAC Gateway authorizes the end‐system with the appropriate policy
or VLAN. If the end‐system is not compliant, the end‐system is restricted access to the network
and the process starts again.
It is important to note that if the wired edge of the network is non‐intelligent (unmanaged
switches and hubs) and is not capable of authenticating and authorizing locally connected end‐
systems, it is possible to augment the network topology to allow implementation of out‐of‐band
NAC with the NAC Gateway. This can be accomplished without replacing the physical edge of the
network, by adding an intelligent edge switch that possesses specialized authentication and
authorization features.
The Enterasys Matrix N‐series switch is capable of authenticating and authorizing numerous end‐
systems connected on a single port through its Multi‐User Authentication (MUA) functionality
and may be positioned upstream from non‐intelligent third‐party edge devices to act as the