What directive controls whether a Samba share allows only guest access?

The directive that controls whether a Samba share allows only guest access is "guest ok." When set to "yes," this directive specifies that unauthenticated users, or guests, are permitted to access the share. This setting is particularly useful in scenarios where minimal authentication is required and access for all users—regardless of whether they have specific credentials—is desired.

By allowing guest access, this directive eases the process of sharing resources in environments where user authentication is not critical, enhancing accessibility for users but also requiring close attention to security risks.

The other options do not accurately reflect the needed directive for allowing only guest access. The "guest only" directive, for instance, typically allows access only to guests, but it would be conditional on both configuration and the presence of guest permissions. "Only guest = yes" is not a valid Samba directive format. "Anonymous access" is a general term describing unauthenticated access but does not specify how Samba implements this access in its configuration.