The string returned in a [18] Reply-Message attribute in a RADIUS Access-Accept is passed to the PPPoE client in the CHAP Success or PAP Authentication-Ack message.
The string returned in a [18] Reply-Message attribute in a RADIUS Access-Reject is passed to the PPPoE client in the CHAP Failure or PAP Authentication-Nak message.
When no [18] Reply-Message attribute is available, the SR OS default messages are used instead: ‟CHAP authentication success” or ‟CHAP authentication failure” for CHAP and ‟Login ok” or ‟Login incorrect” for PAP.