Behaviour

Upon login, anonymous users will be assigned a temporary unique username and resource. For example 1338460e-7076-4d5d-b76a-7c3e4aad32d3@example.com/0b2cfd4d-22d1-4177-8c83-1dfcf5a9cd80.

Although anonymous users have access to everything a normal user would, including roster, vcard and XML store, as soon as they log out it will be removed. If you don't need or want them to have access to these features then you can disable the respective modules with a modules_disabled list in the configuration for that host.

Anonymous hosts

Note that a host with anonymous logins enabled will not allow any other kind of login (eg. with a username/password). If you are mixing authenticated and anonymous services then it is recommended to set up a subdomain for anonymous users, like "anon.example.com".

Allowing access to remote servers

By default Prosody will prevent users on a host configured for anonymous logins from sending messages to other servers (normal non-anonymous hosts on the same server are unaffected). This precaution helps to prevent your server being used as a relay for spammers, bots, and other attackers.

If however you are sure that you want to allow anonymous users to communicate with other services then simply add the allow_anonymous_s2s option to your config, like so:

VirtualHost "anon.example.com"
   -- Enable anonymous login:
   authentication = "anonymous"
 
   -- Allow anonymous users to access remote servers:
   allow_anonymous_s2s = true