Enterasys Networks 9034385 - Manual (Page 96)

Inline NAC Design Procedures
5-32 Design Procedures
3. Identify Backend RADIUS Server Interaction
Layer 2 NAC Controllers detect downstream end‐systems via authentication: MAC, web‐based, or
802.1X. If web‐based or 802.1X authentication is implemented, then a backend RADIUS server
must be configured to validate end user credentials in the authentication process. For each Layer 2
NAC Controller, primary and secondary RADIUS servers may be specified for the validation of
user/device network login credentials on the network.
4. Define Policy Configuration
Policies are assigned to downstream end‐systems on the NAC Controller to authorize connecting
devices with a level of network access. A default set of policies are automatically configured on
each NAC Controller after installation and initialization of the appliance. This set of policies
includes all policies defined by default in NAC Manager, such as Enterprise User, Quarantine,
Assessing, Unregistered, and Failsafe. It is strongly recommended that the policy configurations
of all NAC Controllers are imported into NetSight Policy Manager, reviewed, and appropriately
modified, prior to the full rollout of inline NAC.
Failsafe Policy and Accept Policy Configuration
The Failsafe Policy is assigned to end‐systems when an error occurs in the NAC process. The
Failsafe policy role is configured by default on the NAC Controller to be used as the Failsafe
Policy in NAC Manager. This policy is restrictive, allowing DNS and DHCP, and redirecting web
traffic to serve back a web page stating an error has occurred on the network, while discarding all
other types of traffic.
If it is desired to open network access when an error is encountered, the Enterprise User policy
role can be selected as the Failsafe Policy in the NAC Configuration. The Enterprise User policy
role is fairly open, permitting most types of communication onto the network. For security
purposes the Enterprise User policy role does deny communication to the NAC Controller over
TCP and UDP ports (utilized for administrative purposes, such as RADIUS and SSH). In addition,
the Enterprise User policy discards all communication to NAC Managerʹs IP address for further
security hardening. This policy role can be altered to further control which services a compliant
end‐system is allowed to utilize.
The Accept Policy is assigned to end‐systems when they are deemed compliant. The Enterprise
User policy role is configured by default on the NAC Controller to be used as the Accept Policy in
NAC Manager.
Assessment Policy and Quarantine Policy Configuration
The Assessment Policy and Quarantine Policy are used when end‐system assessment is
implemented in the NAC deployment. The Assessment Policy may be used to temporarily allocate
a set of network resources to end‐systems while they are being assessed. The Assessing policy role
is configured by default on NAC Controllers to be used as the Assessment Policy in NAC
Manager. This policy allows DNS and DHCP, and any traffic destined to the IP address of the
assessment servers deployed on the network. The policy also redirects web traffic to serve back a
web page stating that the end‐system has been restricted access while its security posture is being
determined. All other types of traffic are discarded.
If it is desired to open network access while an end‐system is being assessed, the use of the
Assessment Policy can be disabled in the NAC configuration, or the Enterprise User policy role
can be selected as the Assessment Policy instead. It is important to note that whenever a NAC
configuration is enforced to the NAC Controller, the Assessment Policy is configured to allow