configurable option: force anonymous users to use a Guest- prefix

[slingamn]

This is a ridiculous provocation, but it would be disabled by default obviously. Add a config option that forces all non-SASL'ed users to use a nickname that starts with rename-prefix (defaults to Guest-) --- if their chosen nick doesn't already start with it, prepend it. (Note that nicknames starting with rename-prefix cannot be used as account names, but can be GROUP'ed --- this should be disallowed.)

[slingamn]

Note: this doesn't work well with the current system, where you have to be holding a nick to register it.

[slingamn]

Oh...just strip the Guest- prefix when they NS REGISTER.

[slingamn]

(And do permission checks comparable to a NICK change. And then re-NICK them automatically on verification?)

[slingamn]

This will interact in problematic ways with casefolding and the bidi rule, but it's worth doing anyway.

[clukawski]

I suggest anonymous_coward_ as a prefix

[slingamn]

The guest prefix will be YAML-configurable. Please file your request in the appropriate project: https://github.com/darwin-network/slash

[DanielOaks]

Yeah this makes sense. At the same time, an option to disallow anonymous users entirely would be good (if we don't already have one).

[slingamn]

Yep, that's accounts.require-sasl.