% for interface, config in sorted(interfaces.items()):
interface ${interface}
{
    AdvSendAdvert on;
    prefix ${config.get('prefix', '::/64')}
    {
        AdvOnLink on;
        AdvAutonomous on;
        AdvRouterAddr on;
    };
    RDNSS ${' '.join(sorted(config['rdnss']))}
    {
        AdvRDNSSLifetime 900;
    };
};
% endfor