First configure an Extreme Networks Device as a RADIUS proxy server. See Configure an Extreme Networks RADIUS Proxy.
You can add a postfix notation realm after a user name, separated by an “@” symbol,
and the result resembles an email address domain name. Or you can add a prefix
notation realm before a user name, with a backslash “\” separator. User names can
also include multiple realms, for example domain1.com\username@domain2.com
is a valid user name with two realms.
Realms can be arbitrary text and do not need to contain real domain names, even
though they can look like domains.
This task is part of the network policy configuration workflow. Use this task to configure realms for a RADIUS proxy.
Continue configuring the proxy server.