The value of tmnxSubHttpRdrPlcyUrl specifies the HTTP URL to redirect HTTP traffic to. Actual HTTP redirection is triggered per subscriber during the authentication phase, by the presence of certain vendor- specific attributes in the RADIUS Access-Accept message (Alc-Wifi-Portal-Redirect or Alc-Wifi-Portal-Url). During the set-up of a particular subscriber, this value may be overruled by the value of a vendor-specific attribute in the RADIUS Access-Accept message (Alc-Wifi-Portal-Url). This string may contain a number of substitution macro's: - $URL: specifies that '$URL' must be substituted with the content of the Request-URI in the HTTP GET Request received. - $MAC: specifies that '$MAC' must be replaced with a string that represents the MAC address of the subscriber host; the MAC address is formatted in Nokia SROS style, like 00:0c:f1:99:85:b8. - $IP: specifies that '$IP' must be replaced with a string that represents the IP address of the subscriber host.