Citar ProFTPD: configurar limites
What if a site wished to allow only anonymous access? This would be configured using the LOGIN command group, as above:
<Limit LOGIN>
DenyAll
</Limit>
<Anonymous ~ftp>
<Limit LOGIN>
AllowAll
</Limit>
...
</Anonymous>
The
<Limit>section outside of the<Anonymous>section denies logins to everyone. However, the<Anonymous>section has a<Limit>that allows everyone to login; anonymous logins are allowed, and non-anonymous logins are denied.
P.S. Você pode criar uma seção separada DisplayLogin sorry.msg outside <Anonymous> com o texto "sorry ftp server is only anonymous" no arquivo sorry.msg.