Enterasys Networks 9034385 - Manual (Page 87)

Out-of-Band NAC Design Procedures
Enterasys NAC Design Guide 5-23
It is important to note that only the NAC Gateways that are configured with remediation and
registration functionality need to be positioned in such a manner. All other NAC Gateways may
be positioned at any location on the network, with the only requirement being that access layer
switches are able to communicate to the gateways. Typically, the NAC Gateway with remediation
and registration functionality is positioned on a network segment directly connected to the
distribution layer routers on the enterprise network, so that any HTTP traffic sourced from
quarantined end‐systems that are connected to the networkʹs access layer can be redirected to that
NAC Gateway. As an alternative, the NAC Gateway may be positioned on a network segment
directly connected to the router providing connectivity to the Internet or internal web server farm.
In this scenario, the HTTP traffic sourced from quarantined end‐systems would be redirected to
the NAC Gateway before reaching the Internet or internal web servers.
4. Identify Backend RADIUS Server Interaction
If a NAC Gateway is receiving 802.1X and/or web‐based authentication requests for connecting
end‐systems, then a backend RADIUS server must be configured to validate end user credentials
in the authentication process. For each NAC Gateway, a primary and secondary RADIUS server
can be specified for the validation of user/device network login credentials on the network.
If 802.1X, web‐based, or RADIUS authentication for switch management logins is implemented, a
RADIUS server with backend directory services must be deployed on the network. A RADIUS
server is not necessary if only MAC authentication is deployed on the network.
All RADIUS servers supporting RFC2865 and subsequent RADIUS standards are supported by
Enterasys NAC appliances when proxying RADIUS authentication requests. Tests have been
conducted on the following RADIUS servers:
• FreeRADIUS
• Microsoft IAS
• Funk Steelbelted RADIUS
• Cisco ACS
5. Determine End-System Mobility Restrictions
While Security Domain‐specific MAC and user overrides can be configured to control end‐system
and end user mobility across the network and between Security Domains, the “Lock MAC”
feature allows the network administrator to restrict network access for specific end‐system to a
switch port or switch. The end‐system can be denied network access with a RADIUS Access‐Reject
message returned to the switch, or assigned a specific policy or VLAN when connecting to the
network in a restricted area. Here are some examples of how the Lock MAC feature can be used:
• A printer, server, or other end‐system could be allowed network access only when it is
connected to a port specified by IT operations. This prevents security issues that could result if
the device was moved to a different area of the network.
• An IP phone with a MAC override could be locked to a specific port on a switch. This would
allow exact identification of the phoneʹs location in case an emergency (911) call was placed
from the phone.