Integration with RIPE NCC Access

• From now on, the user authentication behind RIPE Atlas is done through RIPE NCC Access, the RIPE NCC single sign-on system. In order to use RIPE Atlas, you'll have to log in with your single sign-on credentials.
• This change allows us to offer easier access to other RIPE NCC services, as well as to provide more specialised content to RIPE NCC members in the future.