It is a simple auth backend, meant to be used with SASL EXTERNAL authentication mechanism. It simply accepts all usernames as long as they are validated by SASL logic.
Some of its callbacks return hardcoded values, as it's impossible for this backend to properly acquire certain pieces of information. These include:
|PKI reponds with
true to modules checking if user's interlocutor actually exists so e.g. messages to nonexistent users will always be stored by
mod_mam. This is not necessarily a security threat but something to be aware of.
|Any metrics or statistics (e.g. available via
mongooseimctl) related to accounts list or numbers, won't display proper values, as this backend cannot possibly "know" how many users there are.