public InetAddress getRadiusNasIp() throws GuacamoleException {
        try {
            String nasIpStr = environment.getProperty(RadiusGuacamoleProperties.RADIUS_NAS_IP);
            
            // If property is specified and non-empty, attempt to return converted address.
            if (nasIpStr != null && !nasIpStr.isEmpty())
                return InetAddress.getByName(nasIpStr);
            
            // By default, return the address of the server.
            return InetAddress.getLocalHost();
                
        }
        catch (UnknownHostException e) {
            throw new GuacamoleServerException("Unknown host specified for NAS IP.", e);
        }
    }
Returns the InetAddress containing the NAS IP address that should be
used to identify this RADIUS client when communicating with the RADIUS
server. If no explicit configuration of this property is defined
in guacamole.properties, it falls back to attempting to determine the
IP address using Java's built-in mechanisms for querying local addresses.

@return
    The InetAddress corresponding to the NAS IP address specified in
    guacamole.properties, or the IP determined by querying the address
    of the server on which Guacamole is running.

@throws GuacamoleException 
    If guacamole.properties cannot be parsed, or if the InetAddress
    for the NAS IP cannot be read or determined from the system.
extensions/guacamole-auth-radius/src/main/java/org/apache/guacamole/auth/radius/conf/ConfigurationService.java