Enterasys Networks 9034385 - Manual (Page 49)

Scenario 4: VPN Remote Access
Enterasys NAC Design Guide 3-11
Scenario 3 Implementation
In the non‐intelligent access edge use scenario, the five NAC functions are implemented in the
following manner:
1. Detection ‐ The userʹs end‐system connects to the network and transmits data traffic onto the
network that traverses the NAC Controller. This traffic is sourced from a MAC address or IP
address not previously seen by the controller.
2. Authentication ‐ One of two configurations may be implemented on the NAC Controller for
end user authentication. Authentication can be disabled altogether, trusting that the downstream
infrastructure devices authenticated the end‐system to the network (802.1X authentication to the
wireless LAN, web‐based authentication to the wired LAN). Alternatively, MAC registration can
be implemented, where an end user username and password and/or sponsor username and
password must be validated against a backend LDAP‐compliant database before network access is
permitted.
3. Assessment ‐ After the identity of the end‐system or end user is validated by authentication, the
NAC Controller 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
Controllerʹs assessment functionality and/or remotely by a pool of assessment servers.
4. Authorization ‐ Once authentication and assessment are complete, the NAC Controller
allocates the appropriate network resources to the end‐system based on authentication and/or
assessment results. This is implemented locally on the NAC Controller by assigning a policy to
traffic sourced from this end‐system. If authentication fails and/or the assessment results indicate
a noncompliant end‐system, the NAC Controller can either deny the end‐system access to the
network or quarantine the end‐system by specifying a particular policy on the NAC Controller.
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 techniques were successfully followed. If the end‐system is now compliant, the
NAC Controller authorizes the end‐system with the appropriate access policy. If the end‐system is
not compliant, the end‐system is restricted access to the network by assigning a policy to the end‐
system on the NAC Controller, and the process starts again.
Scenario 4: VPN Remote Access
In the VPN remote access use scenario, VPN concentrators act as a termination point for remote
access VPN tunnels into the enterprise network.
For this use scenario, the NAC Controller appliance is deployed to authorize connecting end‐
systems on the network and implement network access control.
The following figure illustrates how the NAC Controller and the other Enterasys NAC
components work together in a VPN remote access deployment to provide a comprehensive NAC
solution.