Nomadix Access Gateways, User Manual, Page: 279 / 330

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Quick Reference Guide 267
RADIUS Attributes
RADIUS (Remote Authentication Dial-In User Service) was originally created to allow remote
authentication to the dial-in networks of corporations and dial-up ISPs. It is defined and
standardized by the IETF (Internet Engineering Task Force) and several RADIUS server
packages exist in both the public domain and for commercial sale.
RADIUS software stores a database of attributes about their valid subscriber base. For
example, usernames, passwords, access privileges, account limits and subscriber attributes can
all be stored in a RADIUS database. RADIUS works in conjunctions with NAS (Network
Access Server) devices to determine if access to the service network should be granted, and if
so, with what privileges.
When a subscriber attempts to access the service provider's network, the Access Gateway
delivers a Web page to the subscriber asking for a login name and password. This information
(password) is encrypted and sent across the network to the ISP's RADIUS server. The
RADIUS server decrypts the information and compares it against its list of valid users. If the
subscriber can be authenticated, the RADIUS server replies to the Access Gatewaywith a
message instructing it to grant access to the subscriber. Optionally, the RADIUS server can
instruct the NAS to perform other functions; for example, the RADIUS server can tell the
Access Gatewaywhat upstream and downstream bandwidth the subscriber should receive. If
RADIUS cannot authenticate the subscriber, it will instruct the NAS to deny access to the
network.
All subscribers attempting to gain access to
the network are validated by RADIUS.
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