Banned users can be configured in the setup file via the banned_users setting. This is a list of user names, or PageSpecs to ban. Using a PageSpec is useful to block an IP address.

For example:

banned_users => ['evilspammer', 'ip('],

If a banned user attempts to use the ikiwiki CGI, they will receive a 403 Forbidden webpage indicating they are banned.

Note that when emailauth is used, the user's email address is displayed in cloaked form in commits of their edits. This cloaked email address can be used as-is in the banned_users setting.