radtest -6 user pass 2001:xxxx:xxxx:xxxx:xxxx::129 0 radiussecret

listen=NO
listen_ipv6=YES
anonymous_enable=NO
local_enable=YES
write_enable=YES
pam_service_name=ftp

auth       sufficient  pam_radius_auth.so
account    sufficient  pam_radius_auth.so

radiusserver radiussecret 10

2001:xxxx:xxxx:xxxx::129 radiusserver.auth radiusserver

ftp localhost
Connected to localhost.
220 (vsFTPd 3.0.2)
Name (localhost:student): user
331 Please specify the password.
Password:
530 Login incorrect.
Login failed.

ubuntu vsftpd: pam_unix(ftp:auth): authentication failure; logname= uid=0 euid=0 tty=ftp ruser=user rhost=::1  user=user

CONNECT: Client "::1"
[user] FAIL LOGIN: Client "::1"